diff --git a/cli/src/pcluster/cli/commands/dcv_util.py b/cli/src/pcluster/cli/commands/dcv_util.py
index d017743d03..d18034c1dc 100644
--- a/cli/src/pcluster/cli/commands/dcv_util.py
+++ b/cli/src/pcluster/cli/commands/dcv_util.py
@@ -16,6 +16,6 @@ def get_supported_dcv_os(architecture):
     """Return a list of all the operating system supported by DCV."""
     architectures_dict = {
         "x86_64": SUPPORTED_OSES,
-        "arm64": ["ubuntu1804", "alinux2", "centos7", "rhel8"],
+        "arm64": ["alinux2", "centos7", "rhel8"],
     }
     return architectures_dict.get(architecture, [])
diff --git a/cli/src/pcluster/constants.py b/cli/src/pcluster/constants.py
index f68555521d..531cdc2598 100644
--- a/cli/src/pcluster/constants.py
+++ b/cli/src/pcluster/constants.py
@@ -23,7 +23,7 @@
 
 SUPPORTED_SCHEDULERS = ["slurm", "awsbatch"]
 SCHEDULERS_SUPPORTING_IMDS_SECURED = ["slurm"]
-SUPPORTED_OSES = ["alinux2", "centos7", "ubuntu1804", "ubuntu2004", "ubuntu2204", "rhel8"]
+SUPPORTED_OSES = ["alinux2", "centos7", "ubuntu2004", "ubuntu2204", "rhel8"]
 SUPPORTED_OSES_FOR_SCHEDULER = {"slurm": SUPPORTED_OSES, "awsbatch": ["alinux2"]}
 DELETE_POLICY = "Delete"
 RETAIN_POLICY = "Retain"
@@ -37,7 +37,6 @@
 OS_MAPPING = {
     "centos7": {"user": "centos"},
     "alinux2": {"user": "ec2-user"},
-    "ubuntu1804": {"user": "ubuntu"},
     "ubuntu2004": {"user": "ubuntu"},
     "ubuntu2204": {"user": "ubuntu"},
     "rhel8": {"user": "ec2-user"},
@@ -46,7 +45,6 @@
 OS_TO_IMAGE_NAME_PART_MAP = {
     "alinux2": "amzn2-hvm",
     "centos7": "centos7-hvm",
-    "ubuntu1804": "ubuntu-1804-lts-hvm",
     "ubuntu2004": "ubuntu-2004-lts-hvm",
     "ubuntu2204": "ubuntu-2204-lts-hvm",
     "rhel8": "rhel8-hvm",
diff --git a/cli/src/pcluster/resources/imagebuilder/parallelcluster.yaml b/cli/src/pcluster/resources/imagebuilder/parallelcluster.yaml
index f2b8fd325a..39b815139e 100644
--- a/cli/src/pcluster/resources/imagebuilder/parallelcluster.yaml
+++ b/cli/src/pcluster/resources/imagebuilder/parallelcluster.yaml
@@ -57,7 +57,7 @@ phases:
               [ -n "${CfnParamCincInstaller}" ] && CINC_URL="${CfnParamCincInstaller}"
               echo "${!CINC_URL}"
 
-      # Check input base AMI OS and get OS information, the output should be like centos.7 | amzn.2 | ubuntu.18.04 | ubuntu.20.04 | ubuntu.22.04 | rhel.8.7
+      # Check input base AMI OS and get OS information, the output should be like centos.7 | amzn.2 | ubuntu.20.04 | ubuntu.22.04 | rhel.8.7
       - name: OperatingSystemRelease
         action: ExecuteBash
         inputs:
@@ -86,8 +86,6 @@ phases:
                 OS='alinux2'
               elif [ `echo "${!RELEASE}" | grep '^centos\.7'` ]; then
                 OS='centos7'
-              elif [ `echo "${!RELEASE}" | grep '^ubuntu\.18'` ]; then
-                OS='ubuntu1804'
               elif [ `echo "${!RELEASE}" | grep '^ubuntu\.20'` ]; then
                 OS='ubuntu2004'
               elif [ `echo "${!RELEASE}" | grep '^ubuntu\.22'` ]; then
@@ -153,10 +151,10 @@ phases:
                   exit {{ FailExitCode }}
                 fi
 
-                # This component only supports aarch64 CPUs on Amazon Linux 2, Ubuntu1804, Ubuntu2004, Ubuntu2204, Centos7 and RHEL8
+                # This component only supports aarch64 CPUs on Amazon Linux 2, Ubuntu2004, Ubuntu2204, Centos7 and RHEL8
                 ARCH=$(uname -m)
                 if [[ `echo ${!ARCH}` == 'aarch64' ]]; then
-                  if [ `echo "${!RELEASE}" | grep -Ev '^(amzn\.2|centos\.7|ubuntu\.18\.04|ubuntu\.20\.04|ubuntu\.22\.04|rhel\.8)'` ]; then
+                  if [ `echo "${!RELEASE}" | grep -Ev '^(amzn\.2|centos\.7|ubuntu\.20\.04|ubuntu\.22\.04|rhel\.8)'` ]; then
                     echo "This component does not support '${!RELEASE}' on ARM64 CPUs. Failing build."
                     exit {{ FailExitCode }}
                   fi
diff --git a/cli/src/pcluster/resources/imagebuilder/parallelcluster_tag.yaml b/cli/src/pcluster/resources/imagebuilder/parallelcluster_tag.yaml
index 1a75164794..3d21b2e9b7 100644
--- a/cli/src/pcluster/resources/imagebuilder/parallelcluster_tag.yaml
+++ b/cli/src/pcluster/resources/imagebuilder/parallelcluster_tag.yaml
@@ -49,8 +49,6 @@ phases:
                 OS='alinux2'
               elif [ $(echo "${RELEASE}" | grep '^centos\.7') ]; then
                 OS='centos7'
-              elif [ $(echo "${RELEASE}" | grep '^ubuntu\.18') ]; then
-                OS='ubuntu1804'
               elif [ $(echo "${RELEASE}" | grep '^ubuntu\.20') ]; then
                 OS='ubuntu2004'
               elif [ $(echo "${RELEASE}" | grep '^ubuntu\.22') ]; then
diff --git a/cli/src/pcluster/resources/imagebuilder/parallelcluster_test.yaml b/cli/src/pcluster/resources/imagebuilder/parallelcluster_test.yaml
index 157fff49db..e69761152d 100644
--- a/cli/src/pcluster/resources/imagebuilder/parallelcluster_test.yaml
+++ b/cli/src/pcluster/resources/imagebuilder/parallelcluster_test.yaml
@@ -38,8 +38,6 @@ phases:
                 OS='alinux2'
               elif [ `echo "${RELEASE}" | grep '^centos\.7'` ]; then
                 OS='centos7'
-              elif [ `echo "${RELEASE}" | grep '^ubuntu\.18'` ]; then
-                OS='ubuntu1804'
               elif [ `echo "${RELEASE}" | grep '^ubuntu\.20'` ]; then
                 OS='ubuntu2004'
               elif [ `echo "${RELEASE}" | grep '^ubuntu\.22'` ]; then
diff --git a/cli/src/pcluster/resources/imagebuilder/parallelcluster_validate.yaml b/cli/src/pcluster/resources/imagebuilder/parallelcluster_validate.yaml
index b88093bcb4..2bfca540c1 100644
--- a/cli/src/pcluster/resources/imagebuilder/parallelcluster_validate.yaml
+++ b/cli/src/pcluster/resources/imagebuilder/parallelcluster_validate.yaml
@@ -38,8 +38,6 @@ phases:
                 OS='alinux2'
               elif [ `echo "${RELEASE}" | grep '^centos\.7'` ]; then
                 OS='centos7'
-              elif [ `echo "${RELEASE}" | grep '^ubuntu\.18'` ]; then
-                OS='ubuntu1804'
               elif [ `echo "${RELEASE}" | grep '^ubuntu\.20'` ]; then
                 OS='ubuntu2004'
               elif [ `echo "${RELEASE}" | grep '^ubuntu\.22'` ]; then
@@ -126,7 +124,7 @@ phases:
               set -v
               ARCHITECTURE='{{ validate.OperatingSystemArchitecture.outputs.stdout }}'
               OS='{{ validate.OperatingSystemName.outputs.stdout }}'
-              if [ ${ARCHITECTURE} == 'arm64' ] && [[ ${OS} =~ ^(ubuntu(18|20|22)04|alinux2|rhel8)$ ]] || [ ${ARCHITECTURE} == 'x86_64' ]; then
+              if [ ${ARCHITECTURE} == 'arm64' ] && [[ ${OS} =~ ^(ubuntu(20|22)04|alinux2|rhel8)$ ]] || [ ${ARCHITECTURE} == 'x86_64' ]; then
                 echo "true"
               else
                 echo "false"
@@ -326,8 +324,6 @@ phases:
                 echo "Checking for Lustre client..."
                 if [ ${OS} == centos7 ]; then
                   rpm -qa | grep lustre-client
-                elif [ ${OS} == ubuntu1804 ]; then
-                  dpkg -l | grep lustre
                 fi
               fi
               [[ $? -ne 0 ]] && echo "Check for Lustre client failed" && exit 1
diff --git a/cli/src/pcluster/resources/imagebuilder/update_and_reboot.yaml b/cli/src/pcluster/resources/imagebuilder/update_and_reboot.yaml
index 66a89bcbfd..5ce980737a 100644
--- a/cli/src/pcluster/resources/imagebuilder/update_and_reboot.yaml
+++ b/cli/src/pcluster/resources/imagebuilder/update_and_reboot.yaml
@@ -10,7 +10,7 @@ constants:
 phases:
   - name: build
     steps:
-      # Check input base AMI OS and get OS information, the output should be like centos.7 | amzn.2 | ubuntu.18.04 | ubuntu.20.04 | ubuntu.22.04 | rhel.8.7
+      # Check input base AMI OS and get OS information, the output should be like centos.7 | amzn.2 | ubuntu.20.04 | ubuntu.22.04 | rhel.8.7
       - name: OperatingSystemRelease
         action: ExecuteBash
         inputs:
@@ -39,8 +39,6 @@ phases:
                 OS='alinux2'
               elif [ `echo "${!RELEASE}" | grep '^centos\.7'` ]; then
                 OS='centos7'
-              elif [ `echo "${!RELEASE}" | grep '^ubuntu\.18'` ]; then
-                OS='ubuntu1804'
               elif [ `echo "${!RELEASE}" | grep '^ubuntu\.20'` ]; then
                 OS='ubuntu2004'
               elif [ `echo "${!RELEASE}" | grep '^ubuntu\.22'` ]; then
@@ -84,10 +82,10 @@ phases:
                 exit {{ FailExitCode }}
               fi
 
-              # This component only supports aarch64 CPUs on Amazon Linux 2, Ubuntu1804, Ubuntu2004, Ubuntu2204, Centos7 and RHEL 8
+              # This component only supports aarch64 CPUs on Amazon Linux 2, Ubuntu2004, Ubuntu2204, Centos7 and RHEL 8
               ARCH=$(uname -m)
               if [[ `echo ${!ARCH}` == 'aarch64' ]]; then
-                if [ `echo "${!RELEASE}" | grep -Ev '^(amzn\.2|centos\.7|ubuntu\.18\.04|ubuntu\.20\.04|ubuntu\.22\.04|rhel\.8)'` ]; then
+                if [ `echo "${!RELEASE}" | grep -Ev '^(amzn\.2|centos\.7|ubuntu\.20\.04|ubuntu\.22\.04|rhel\.8)'` ]; then
                   echo "This component does not support '${!RELEASE}' on ARM64 CPUs. Failing build."
                   exit {{ FailExitCode }}
                 fi
diff --git a/cli/src/pcluster/templates/cw_dashboard_builder.py b/cli/src/pcluster/templates/cw_dashboard_builder.py
index 23c7216d1b..1ec51713a5 100644
--- a/cli/src/pcluster/templates/cw_dashboard_builder.py
+++ b/cli/src/pcluster/templates/cw_dashboard_builder.py
@@ -710,7 +710,7 @@ def _add_cw_log(self):
                     ),
                     self._new_cw_log_widget(
                         title="syslog",
-                        conditions=[Condition(["ubuntu1804", "ubuntu2004", "ubuntu2204"], base_os)],
+                        conditions=[Condition(["ubuntu2004", "ubuntu2204"], base_os)],
                         filters=[self._new_filter(pattern=f"{head_private_ip}.*syslog")],
                     ),
                     self._new_cw_log_widget(
diff --git a/cli/tests/pcluster/cli/configure/test_pcluster_configure.py b/cli/tests/pcluster/cli/configure/test_pcluster_configure.py
index 176e092368..21ca0ccc82 100644
--- a/cli/tests/pcluster/cli/configure/test_pcluster_configure.py
+++ b/cli/tests/pcluster/cli/configure/test_pcluster_configure.py
@@ -453,7 +453,7 @@ def _run_input_test(
 ):
     if with_input:
         input_composer = ComposeInput(aws_region_name="us-east-1", key="key2", scheduler="slurm")
-        input_composer.add_first_flow(op_sys="ubuntu1804", head_node_instance=head_node_instance)
+        input_composer.add_first_flow(op_sys="ubuntu2004", head_node_instance=head_node_instance)
         input_composer.add_compute_instance(compute_instance, "18")
         input_composer.add_no_automation_no_empty_vpc(
             vpc_id="vpc-34567891", head_node_id="subnet-34567891", compute_id="subnet-45678912"
diff --git a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_disabled_efa_no_placement_group/output.txt b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_disabled_efa_no_placement_group/output.txt
index 7c64b19738..199b813ba2 100644
--- a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_disabled_efa_no_placement_group/output.txt
+++ b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_disabled_efa_no_placement_group/output.txt
@@ -32,10 +32,9 @@ Allowed values for Scheduler:
 Allowed values for Operating System:
 1. alinux2
 2. centos7
-3. ubuntu1804
-4. ubuntu2004
-5. ubuntu2204
-6. rhel8
+3. ubuntu2004
+4. ubuntu2204
+5. rhel8
 The EC2 instance selected supports enhanced networking capabilities using Elastic Fabric Adapter (EFA). EFA enables you to run applications requiring high levels of inter-node communications at scale on AWS at no additional charge (https://docs.aws.amazon.com/parallelcluster/latest/ug/efa-v3.html).
 Allowed values for VPC ID:
   #  id            name                                 number_of_subnets
diff --git a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_efa_not_supported/output.txt b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_efa_not_supported/output.txt
index 71c701d079..0ce60fd221 100644
--- a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_efa_not_supported/output.txt
+++ b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_efa_not_supported/output.txt
@@ -32,10 +32,9 @@ Allowed values for Scheduler:
 Allowed values for Operating System:
 1. alinux2
 2. centos7
-3. ubuntu1804
-4. ubuntu2004
-5. ubuntu2204
-6. rhel8
+3. ubuntu2004
+4. ubuntu2204
+5. rhel8
 Allowed values for VPC ID:
   #  id            name                                 number_of_subnets
 ---  ------------  ---------------------------------  -------------------
diff --git a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_enabled_efa_default_placement_group/output.txt b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_enabled_efa_default_placement_group/output.txt
index 79828eaecd..1ce7ae1c55 100644
--- a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_enabled_efa_default_placement_group/output.txt
+++ b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_enabled_efa_default_placement_group/output.txt
@@ -32,10 +32,9 @@ Allowed values for Scheduler:
 Allowed values for Operating System:
 1. alinux2
 2. centos7
-3. ubuntu1804
-4. ubuntu2004
-5. ubuntu2204
-6. rhel8
+3. ubuntu2004
+4. ubuntu2204
+5. rhel8
 The EC2 instance selected supports enhanced networking capabilities using Elastic Fabric Adapter (EFA). EFA enables you to run applications requiring high levels of inter-node communications at scale on AWS at no additional charge (https://docs.aws.amazon.com/parallelcluster/latest/ug/efa-v3.html).
 Enabling EFA requires compute instances to be placed within a Placement Group. Please specify an existing Placement Group name or leave it blank for ParallelCluster to create one.
 Allowed values for VPC ID:
diff --git a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_enabled_efa_existing_placement_group/output.txt b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_enabled_efa_existing_placement_group/output.txt
index 79828eaecd..1ce7ae1c55 100644
--- a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_enabled_efa_existing_placement_group/output.txt
+++ b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_enabled_efa_existing_placement_group/output.txt
@@ -32,10 +32,9 @@ Allowed values for Scheduler:
 Allowed values for Operating System:
 1. alinux2
 2. centos7
-3. ubuntu1804
-4. ubuntu2004
-5. ubuntu2204
-6. rhel8
+3. ubuntu2004
+4. ubuntu2204
+5. rhel8
 The EC2 instance selected supports enhanced networking capabilities using Elastic Fabric Adapter (EFA). EFA enables you to run applications requiring high levels of inter-node communications at scale on AWS at no additional charge (https://docs.aws.amazon.com/parallelcluster/latest/ug/efa-v3.html).
 Enabling EFA requires compute instances to be placed within a Placement Group. Please specify an existing Placement Group name or leave it blank for ParallelCluster to create one.
 Allowed values for VPC ID:
diff --git a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_enabled_efa_non_existent_placement_group/output.txt b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_enabled_efa_non_existent_placement_group/output.txt
index cb0308924f..41b755cf78 100644
--- a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_enabled_efa_non_existent_placement_group/output.txt
+++ b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_enabled_efa_non_existent_placement_group/output.txt
@@ -32,10 +32,9 @@ Allowed values for Scheduler:
 Allowed values for Operating System:
 1. alinux2
 2. centos7
-3. ubuntu1804
-4. ubuntu2004
-5. ubuntu2204
-6. rhel8
+3. ubuntu2004
+4. ubuntu2204
+5. rhel8
 The EC2 instance selected supports enhanced networking capabilities using Elastic Fabric Adapter (EFA). EFA enables you to run applications requiring high levels of inter-node communications at scale on AWS at no additional charge (https://docs.aws.amazon.com/parallelcluster/latest/ug/efa-v3.html).
 Enabling EFA requires compute instances to be placed within a Placement Group. Please specify an existing Placement Group name or leave it blank for ParallelCluster to create one.
 ERROR: non-existent-test-pg is not an acceptable value for Placement Group name
diff --git a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_filtered_subnets_by_az/output.txt b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_filtered_subnets_by_az/output.txt
index 268bedf537..a776645ca9 100644
--- a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_filtered_subnets_by_az/output.txt
+++ b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_filtered_subnets_by_az/output.txt
@@ -32,10 +32,9 @@ Allowed values for Scheduler:
 Allowed values for Operating System:
 1. alinux2
 2. centos7
-3. ubuntu1804
-4. ubuntu2004
-5. ubuntu2204
-6. rhel8
+3. ubuntu2004
+4. ubuntu2204
+5. rhel8
 Allowed values for VPC ID:
   #  id            name                                 number_of_subnets
 ---  ------------  ---------------------------------  -------------------
diff --git a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_no_automation_no_awsbatch_no_errors/output.txt b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_no_automation_no_awsbatch_no_errors/output.txt
index 71c701d079..0ce60fd221 100644
--- a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_no_automation_no_awsbatch_no_errors/output.txt
+++ b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_no_automation_no_awsbatch_no_errors/output.txt
@@ -32,10 +32,9 @@ Allowed values for Scheduler:
 Allowed values for Operating System:
 1. alinux2
 2. centos7
-3. ubuntu1804
-4. ubuntu2004
-5. ubuntu2204
-6. rhel8
+3. ubuntu2004
+4. ubuntu2204
+5. rhel8
 Allowed values for VPC ID:
   #  id            name                                 number_of_subnets
 ---  ------------  ---------------------------------  -------------------
diff --git a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_no_input_no_automation_no_errors/output.txt b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_no_input_no_automation_no_errors/output.txt
index 8356af3db4..36bce13d99 100644
--- a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_no_input_no_automation_no_errors/output.txt
+++ b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_no_input_no_automation_no_errors/output.txt
@@ -32,10 +32,9 @@ Allowed values for Scheduler:
 Allowed values for Operating System:
 1. alinux2
 2. centos7
-3. ubuntu1804
-4. ubuntu2004
-5. ubuntu2204
-6. rhel8
+3. ubuntu2004
+4. ubuntu2204
+5. rhel8
 Allowed values for VPC ID:
   #  id            name                                 number_of_subnets
 ---  ------------  ---------------------------------  -------------------
diff --git a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_subnet_automation_no_awsbatch_no_errors/output.txt b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_subnet_automation_no_awsbatch_no_errors/output.txt
index 6efbc12586..a2002be580 100644
--- a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_subnet_automation_no_awsbatch_no_errors/output.txt
+++ b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_subnet_automation_no_awsbatch_no_errors/output.txt
@@ -32,10 +32,9 @@ Allowed values for Scheduler:
 Allowed values for Operating System:
 1. alinux2
 2. centos7
-3. ubuntu1804
-4. ubuntu2004
-5. ubuntu2204
-6. rhel8
+3. ubuntu2004
+4. ubuntu2204
+5. rhel8
 Allowed values for VPC ID:
   #  id            name                                 number_of_subnets
 ---  ------------  ---------------------------------  -------------------
diff --git a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_subnet_automation_no_awsbatch_no_errors_empty_vpc/output.txt b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_subnet_automation_no_awsbatch_no_errors_empty_vpc/output.txt
index c61631a849..6983189c5e 100644
--- a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_subnet_automation_no_awsbatch_no_errors_empty_vpc/output.txt
+++ b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_subnet_automation_no_awsbatch_no_errors_empty_vpc/output.txt
@@ -32,10 +32,9 @@ Allowed values for Scheduler:
 Allowed values for Operating System:
 1. alinux2
 2. centos7
-3. ubuntu1804
-4. ubuntu2004
-5. ubuntu2204
-6. rhel8
+3. ubuntu2004
+4. ubuntu2204
+5. rhel8
 Allowed values for VPC ID:
   #  id            name                                 number_of_subnets
 ---  ------------  ---------------------------------  -------------------
diff --git a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_vpc_automation_no_awsbatch_no_errors/output.txt b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_vpc_automation_no_awsbatch_no_errors/output.txt
index 0ac20e1547..5e99a2271b 100644
--- a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_vpc_automation_no_awsbatch_no_errors/output.txt
+++ b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_vpc_automation_no_awsbatch_no_errors/output.txt
@@ -32,10 +32,9 @@ Allowed values for Scheduler:
 Allowed values for Operating System:
 1. alinux2
 2. centos7
-3. ubuntu1804
-4. ubuntu2004
-5. ubuntu2204
-6. rhel8
+3. ubuntu2004
+4. ubuntu2204
+5. rhel8
 Allowed values for Availability Zone:
 1. eu-west-1a
 2. eu-west-1b
diff --git a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_vpc_automation_no_vpc_in_region/output.txt b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_vpc_automation_no_vpc_in_region/output.txt
index a7b4dbe924..07ce5df835 100644
--- a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_vpc_automation_no_vpc_in_region/output.txt
+++ b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_vpc_automation_no_vpc_in_region/output.txt
@@ -32,10 +32,9 @@ Allowed values for Scheduler:
 Allowed values for Operating System:
 1. alinux2
 2. centos7
-3. ubuntu1804
-4. ubuntu2004
-5. ubuntu2204
-6. rhel8
+3. ubuntu2004
+4. ubuntu2204
+5. rhel8
 There are no VPC for the given region. Starting automatic creation of VPC and subnets...
 Allowed values for Availability Zone:
 1. eu-west-1a
diff --git a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_vpc_automation_no_vpc_in_region_public/output.txt b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_vpc_automation_no_vpc_in_region_public/output.txt
index a7b4dbe924..07ce5df835 100644
--- a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_vpc_automation_no_vpc_in_region_public/output.txt
+++ b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_vpc_automation_no_vpc_in_region_public/output.txt
@@ -32,10 +32,9 @@ Allowed values for Scheduler:
 Allowed values for Operating System:
 1. alinux2
 2. centos7
-3. ubuntu1804
-4. ubuntu2004
-5. ubuntu2204
-6. rhel8
+3. ubuntu2004
+4. ubuntu2204
+5. rhel8
 There are no VPC for the given region. Starting automatic creation of VPC and subnets...
 Allowed values for Availability Zone:
 1. eu-west-1a
diff --git a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_with_region_arg/output.txt b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_with_region_arg/output.txt
index 41e581727e..e8ed1ed8d8 100644
--- a/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_with_region_arg/output.txt
+++ b/cli/tests/pcluster/cli/configure/test_pcluster_configure/test_with_region_arg/output.txt
@@ -15,10 +15,9 @@ Allowed values for Scheduler:
 Allowed values for Operating System:
 1. alinux2
 2. centos7
-3. ubuntu1804
-4. ubuntu2004
-5. ubuntu2204
-6. rhel8
+3. ubuntu2004
+4. ubuntu2204
+5. rhel8
 Allowed values for VPC ID:
   #  id            name                                 number_of_subnets
 ---  ------------  ---------------------------------  -------------------
diff --git a/cli/tests/pcluster/cli/configure/test_pcluster_configure_utils.py b/cli/tests/pcluster/cli/configure/test_pcluster_configure_utils.py
index e2f981ea9b..e9e959c2e3 100644
--- a/cli/tests/pcluster/cli/configure/test_pcluster_configure_utils.py
+++ b/cli/tests/pcluster/cli/configure/test_pcluster_configure_utils.py
@@ -14,7 +14,7 @@
         ("Scheduler", ["awsbatch"], "slurm", None),
         ("Operating System", None, "alinux2", None),
         ("Operating System", [], "alinux2", None),
-        ("Operating System", ["centos7", "ubuntu1804"], "alinux2", None),
+        ("Operating System", ["centos7", "ubuntu2004"], "alinux2", None),
         # Ensure first item is selected from first nested list/tuple
         ("fake-parameter", [{"id": "a", "key2": "b"}, {"id": "c", "key3": "d"}], "a", None),
         ("fake-parameter", ({"id": "a", "key2": "b"}, {"id": "c", "key3": "d"}), "a", None),
diff --git a/cli/tests/pcluster/cli/test_describe_image.py b/cli/tests/pcluster/cli/test_describe_image.py
index b0859d601a..7308f2681d 100644
--- a/cli/tests/pcluster/cli/test_describe_image.py
+++ b/cli/tests/pcluster/cli/test_describe_image.py
@@ -42,14 +42,14 @@ def test_execute(self, mocker):
             "imageConfiguration": {
                 "url": "s3://parallelcluster-0000000000000000-v1-do-not-delete/parallelcluster/3.0.0/config.yaml"
             },
-            "imageId": "aws-parallelcluster-3-0-0-ubuntu-1804-lts-hvm-arm64-202101010000",
+            "imageId": "aws-parallelcluster-3-0-0-ubuntu-2004-lts-hvm-arm64-202101010000",
             "creationTime": "2021-01-01T00:00:00.000Z",
             "imageBuildStatus": "BUILD_COMPLETE",
             "region": "eu-west-2",
             "ec2AmiInfo": {
-                "amiName": "aws-parallelcluster-3.0.0-ubuntu-1804-lts-hvm-x86_64-202101010000 2021-01-01T00-00-00.000Z",
+                "amiName": "aws-parallelcluster-3.0.0-ubuntu-2004-lts-hvm-x86_64-202101010000 2021-01-01T00-00-00.000Z",
                 "amiId": "ami-FEED0DEAD0BEEF000",
-                "description": "AWS ParallelCluster AMI for ubuntu1804",
+                "description": "AWS ParallelCluster AMI for ubuntu2004",
                 "state": "AVAILABLE",
                 "tags": [
                     {"key": "parallelcluster:lustre_version", "value": "5.4.0.1051.33"},
diff --git a/cli/tests/pcluster/example_configs/awsbatch.full.yaml b/cli/tests/pcluster/example_configs/awsbatch.full.yaml
index 0c7515b7eb..87875520bc 100644
--- a/cli/tests/pcluster/example_configs/awsbatch.full.yaml
+++ b/cli/tests/pcluster/example_configs/awsbatch.full.yaml
@@ -2,7 +2,7 @@ Imds:
   ImdsSupport: v2.0
 Region: us-east-1
 Image:
-  Os: alinux2  # alinux2 | centos7 | ubuntu1804 | ubuntu2004
+  Os: alinux2  # alinux2 | centos7 | ubuntu2004
   CustomAmi: ami-12345678
 HeadNode:
   InstanceType: t2.micro
diff --git a/cli/tests/pcluster/schemas/test_cluster_schema.py b/cli/tests/pcluster/schemas/test_cluster_schema.py
index b334e78ab5..7e6e51f5d2 100644
--- a/cli/tests/pcluster/schemas/test_cluster_schema.py
+++ b/cli/tests/pcluster/schemas/test_cluster_schema.py
@@ -71,7 +71,7 @@ def test_cluster_schema_awsbatch(mocker, test_datadir, config_file_name):
     "os, custom_ami, failure_message",
     [
         (None, None, "Missing data for required field"),
-        ("ubuntu1804", "ami-12345678", None),
+        ("ubuntu2004", "ami-12345678", None),
         ("centos7", None, None),
     ],
 )
diff --git a/cli/tests/pcluster/templates/test_cw_dashboard_builder.py b/cli/tests/pcluster/templates/test_cw_dashboard_builder.py
index 99364f423b..7b235c2299 100644
--- a/cli/tests/pcluster/templates/test_cw_dashboard_builder.py
+++ b/cli/tests/pcluster/templates/test_cw_dashboard_builder.py
@@ -30,11 +30,11 @@
         ("centos7.slurm.full.yaml", "us-east-1"),
         ("rhel8.slurm.full.yaml", "us-east-1"),
         ("alinux2.slurm.conditional_vol.yaml", "us-east-1"),
-        ("ubuntu18.slurm.simple.yaml", "us-east-1"),
+        ("ubuntu20.slurm.simple.yaml", "us-east-1"),
         ("alinux2.batch.no_head_node_log.yaml", "us-east-1"),
-        ("ubuntu18.slurm.no_dashboard.yaml", "us-east-1"),
+        ("ubuntu20.slurm.no_dashboard.yaml", "us-east-1"),
         ("alinux2.batch.head_node_log.yaml", "us-east-1"),
-        ("ubuntu18.slurm.simple.yaml", "us-iso-WHATEVER"),
+        ("ubuntu20.slurm.simple.yaml", "us-iso-WHATEVER"),
     ],
 )
 def test_cw_dashboard_builder(mocker, test_datadir, set_env, config_file_name, region):
@@ -197,7 +197,7 @@ def _verify_head_node_logs_conditions(cluster_config, output_yaml):
     if cluster_config.image.os in ["alinux2", "centos7", "rhel8"]:
         assert_that(output_yaml).contains("system-messages")
         assert_that(output_yaml).does_not_contain("syslog")
-    elif cluster_config.image.os in ["ubuntu1804"]:
+    elif cluster_config.image.os in ["ubuntu2004"]:
         assert_that(output_yaml).contains("syslog")
         assert_that(output_yaml).does_not_contain("system-messages")
 
diff --git a/cli/tests/pcluster/templates/test_cw_dashboard_builder/test_cw_dashboard_builder/ubuntu18.slurm.no_dashboard.yaml b/cli/tests/pcluster/templates/test_cw_dashboard_builder/test_cw_dashboard_builder/ubuntu20.slurm.no_dashboard.yaml
similarity index 99%
rename from cli/tests/pcluster/templates/test_cw_dashboard_builder/test_cw_dashboard_builder/ubuntu18.slurm.no_dashboard.yaml
rename to cli/tests/pcluster/templates/test_cw_dashboard_builder/test_cw_dashboard_builder/ubuntu20.slurm.no_dashboard.yaml
index 71ade80c95..a90103f1ff 100644
--- a/cli/tests/pcluster/templates/test_cw_dashboard_builder/test_cw_dashboard_builder/ubuntu18.slurm.no_dashboard.yaml
+++ b/cli/tests/pcluster/templates/test_cw_dashboard_builder/test_cw_dashboard_builder/ubuntu20.slurm.no_dashboard.yaml
@@ -1,5 +1,5 @@
 Image:
-  Os: ubuntu1804
+  Os: ubuntu2004
 HeadNode:
   InstanceType: t2.micro
   Networking:
diff --git a/cli/tests/pcluster/templates/test_cw_dashboard_builder/test_cw_dashboard_builder/ubuntu18.slurm.simple.yaml b/cli/tests/pcluster/templates/test_cw_dashboard_builder/test_cw_dashboard_builder/ubuntu20.slurm.simple.yaml
similarity index 98%
rename from cli/tests/pcluster/templates/test_cw_dashboard_builder/test_cw_dashboard_builder/ubuntu18.slurm.simple.yaml
rename to cli/tests/pcluster/templates/test_cw_dashboard_builder/test_cw_dashboard_builder/ubuntu20.slurm.simple.yaml
index 84b9deec25..7ea98847ca 100644
--- a/cli/tests/pcluster/templates/test_cw_dashboard_builder/test_cw_dashboard_builder/ubuntu18.slurm.simple.yaml
+++ b/cli/tests/pcluster/templates/test_cw_dashboard_builder/test_cw_dashboard_builder/ubuntu20.slurm.simple.yaml
@@ -1,5 +1,5 @@
 Image:
-  Os: ubuntu1804
+  Os: ubuntu2004
 HeadNode:
   InstanceType: t2.micro
   Networking:
diff --git a/cli/tests/pcluster/test_utils.py b/cli/tests/pcluster/test_utils.py
index 2bd167f2e0..0086c3f928 100644
--- a/cli/tests/pcluster/test_utils.py
+++ b/cli/tests/pcluster/test_utils.py
@@ -86,8 +86,8 @@ def test_generate_random_prefix():
 @pytest.mark.parametrize(
     "architecture, supported_oses",
     [
-        ("x86_64", ["alinux2", "centos7", "ubuntu1804", "ubuntu2004", "ubuntu2204", "rhel8"]),
-        ("arm64", ["alinux2", "centos7", "ubuntu1804", "ubuntu2004", "ubuntu2204", "rhel8"]),
+        ("x86_64", ["alinux2", "centos7", "ubuntu2004", "ubuntu2204", "rhel8"]),
+        ("arm64", ["alinux2", "centos7", "ubuntu2004", "ubuntu2204", "rhel8"]),
     ],
 )
 def test_get_supported_os_for_architecture(architecture, supported_oses):
@@ -100,7 +100,7 @@ def test_get_supported_os_for_architecture(architecture, supported_oses):
 @pytest.mark.parametrize(
     "scheduler, supported_oses",
     [
-        ("slurm", ["alinux2", "centos7", "ubuntu1804", "ubuntu2004", "ubuntu2204", "rhel8"]),
+        ("slurm", ["alinux2", "centos7", "ubuntu2004", "ubuntu2204", "rhel8"]),
         ("awsbatch", ["alinux2"]),
     ],
 )
diff --git a/cli/tests/pcluster/validators/test_cluster_validators.py b/cli/tests/pcluster/validators/test_cluster_validators.py
index 49c7244fea..8fe79a1895 100644
--- a/cli/tests/pcluster/validators/test_cluster_validators.py
+++ b/cli/tests/pcluster/validators/test_cluster_validators.py
@@ -461,10 +461,10 @@ def test_region_validator(region, expected_message):
     "os, scheduler, expected_message",
     [
         ("centos7", "slurm", None),
-        ("ubuntu1804", "slurm", None),
         ("ubuntu2004", "slurm", None),
         ("alinux2", "slurm", None),
         ("rhel8", "slurm", None),
+        ("ubuntu1804", "slurm", "scheduler supports the following operating systems"),
         ("centos7", "awsbatch", "scheduler supports the following operating systems"),
         ("rhel8", "awsbatch", "scheduler supports the following operating systems"),
         ("ubuntu1804", "awsbatch", "scheduler supports the following operating systems"),
@@ -825,7 +825,13 @@ def test_efa_multi_az_validator(multi_az_enabled, efa_enabled, expected_message)
         ("rhel8", "x86_64", "custom-ami", None, None),
         ("centos7", "x86_64", None, None, None),
         ("centos7", "x86_64", "custom-ami", None, None),
-        ("ubuntu1804", "x86_64", None, None, None),
+        (
+            "ubuntu1804",
+            "x86_64",
+            None,
+            None,
+            "The architecture x86_64 is only supported for the following operating systems",
+        ),
         ("ubuntu2004", "x86_64", None, None, None),
         # All OSes supported for ARM
         ("alinux2", "arm64", None, None, None),
@@ -839,7 +845,13 @@ def test_efa_multi_az_validator(multi_az_enabled, efa_enabled, expected_message)
         ),
         ("centos7", "arm64", None, {"ami_search_filters"}, None),
         ("centos7", "arm64", "custom-ami", None, None),
-        ("ubuntu1804", "arm64", None, None, None),
+        (
+            "ubuntu1804",
+            "arm64",
+            None,
+            None,
+            "The architecture arm64 is only supported for the following operating systems",
+        ),
         ("ubuntu2004", "arm64", None, None, None),
         ("rhel8", "arm64", None, None, None),
         ("rhel8", "arm64", "custom-ami", None, None),
@@ -1298,13 +1310,25 @@ def test_fsx_network_validator(
         ("x86_64", "alinux2", None),
         ("x86_64", "centos7", None),
         ("x86_64", "rhel8", None),
-        ("x86_64", "ubuntu1804", None),
         ("x86_64", "ubuntu2004", None),
-        ("arm64", "ubuntu1804", None),
         ("arm64", "ubuntu2004", None),
         ("arm64", "rhel8", None),
         ("arm64", "alinux2", None),
         # Unsupported combinations
+        (
+            "x86_64",
+            "ubuntu1804",
+            FSX_MESSAGES["errors"]["unsupported_os"].format(
+                architecture="x86_64", supported_oses=FSX_SUPPORTED_ARCHITECTURES_OSES.get("x86_64")
+            ),
+        ),
+        (
+            "arm64",
+            "ubuntu1804",
+            FSX_MESSAGES["errors"]["unsupported_os"].format(
+                architecture="arm64", supported_oses=FSX_SUPPORTED_ARCHITECTURES_OSES.get("arm64")
+            ),
+        ),
         (
             "UnsupportedArchitecture",
             "alinux2",
@@ -1473,16 +1497,14 @@ def test_shared_storage_mount_dir_validator(mount_dir, expected_message):
     "dcv_enabled, os, instance_type, allowed_ips, port, expected_message",
     [
         (True, "centos7", "t2.medium", None, None, None),
-        (True, "ubuntu1804", "t2.medium", None, None, None),
         (True, "rhel8", "t2.medium", None, None, None),
-        (True, "ubuntu1804", "t2.medium", None, "1.2.3.4/32", None),
+        (True, "ubuntu1804", "t2.medium", None, "1.2.3.4/32", "Please double check the os configuration"),
         (True, "ubuntu2004", "t2.medium", None, None, None),
         (True, "centos7", "t2.medium", "0.0.0.0/0", 8443, "port 8443 to the world"),
         (True, "alinux2", "t2.medium", None, None, None),
         (True, "alinux2", "t2.nano", None, None, "is recommended to use an instance type with at least"),
         (True, "alinux2", "t2.micro", None, None, "is recommended to use an instance type with at least"),
         (False, "alinux2", "t2.micro", None, None, None),  # doesn't fail because DCV is disabled
-        (True, "ubuntu1804", "m6g.xlarge", None, None, None),
         (True, "alinux2", "m6g.xlarge", None, None, None),
         (True, "rhel8", "m6g.xlarge", None, None, None),
         (True, "ubuntu2004", "m6g.xlarge", None, None, "Please double check the os configuration"),
diff --git a/cli/tests/pcluster/validators/test_ec2_validators.py b/cli/tests/pcluster/validators/test_ec2_validators.py
index 4e2995cf9d..c6a5f3aaca 100644
--- a/cli/tests/pcluster/validators/test_ec2_validators.py
+++ b/cli/tests/pcluster/validators/test_ec2_validators.py
@@ -383,8 +383,8 @@ def test_capacity_type_validator(mocker, capacity_type, supported_usage_classes,
         (
             "ami-111111111111",
             "alinux2",
-            ImageInfo({"Tags": [{"Key": "parallelcluster:os", "Value": "ubuntu1804"}]}),
-            "The OS of node AMI ami-111111111111 is ubuntu1804, it is not compatible with cluster OS alinux2.",
+            ImageInfo({"Tags": [{"Key": "parallelcluster:os", "Value": "ubuntu2004"}]}),
+            "The OS of node AMI ami-111111111111 is ubuntu2004, it is not compatible with cluster OS alinux2.",
         ),
         (
             "ami-222222222222",
diff --git a/tests/integration-tests/configs/byos.yaml b/tests/integration-tests/configs/byos.yaml
index baacd8cf38..37c89a9909 100644
--- a/tests/integration-tests/configs/byos.yaml
+++ b/tests/integration-tests/configs/byos.yaml
@@ -6,7 +6,7 @@ test-suites:
       dimensions:
         - regions: [ "ap-northeast-2" ]
           instances: {{ common.INSTANCES_DEFAULT_X86 }}
-          oss: [ "ubuntu1804" ]
+          oss: [ "ubuntu2004" ]
           schedulers: [ "slurm" ]
   schedulers:
     test_slurm.py::test_slurm:
diff --git a/tests/integration-tests/configs/common.jinja2 b/tests/integration-tests/configs/common.jinja2
index 923619b216..357c3b7d2c 100644
--- a/tests/integration-tests/configs/common.jinja2
+++ b/tests/integration-tests/configs/common.jinja2
@@ -5,12 +5,12 @@
 {%- set SCHEDULERS_ALL = ["slurm", "awsbatch"] -%}
 {%- set SCHEDULERS_TRAD = ["slurm"] -%}
 {%- set OSS_BATCH = ["alinux2"] -%}
-{%- set OSS_COMMERCIAL_X86 = ["alinux2", "centos7", "ubuntu1804", "ubuntu2004", "rhel8"] -%}
-{%- set OSS_CHINA_X86 = ["alinux2", "ubuntu1804", "ubuntu2004", "rhel8"] -%}
-{%- set OSS_GOVCLOUD_X86 = ["alinux2", "ubuntu1804", "ubuntu2004", "rhel8"] -%}
-{%- set OSS_COMMERCIAL_ARM = ["alinux2", "ubuntu1804", "ubuntu2004", "rhel8"] -%}
-{%- set OSS_CHINA_ARM = ["alinux2", "ubuntu1804", "ubuntu2004", "rhel8"] -%}
-{%- set OSS_GOVCLOUD_ARM = ["alinux2", "ubuntu1804", "ubuntu2004", "rhel8"] -%}
+{%- set OSS_COMMERCIAL_X86 = ["alinux2", "centos7", "ubuntu2004", "rhel8"] -%}
+{%- set OSS_CHINA_X86 = ["alinux2", "ubuntu2004", "rhel8"] -%}
+{%- set OSS_GOVCLOUD_X86 = ["alinux2", "ubuntu2004", "rhel8"] -%}
+{%- set OSS_COMMERCIAL_ARM = ["alinux2", "ubuntu2004", "rhel8"] -%}
+{%- set OSS_CHINA_ARM = ["alinux2", "ubuntu2004", "rhel8"] -%}
+{%- set OSS_GOVCLOUD_ARM = ["alinux2", "ubuntu2004", "rhel8"] -%}
 {%- set OSS_ONE_PER_DISTRO = ["centos7", "alinux2", "ubuntu2004", "rhel8"] -%}
 {%- set INSTANCES_DEFAULT_X86 = ["c5.xlarge"] -%}
 {%- set INSTANCES_DEFAULT_ARM = ["m6g.xlarge"] -%} # m6g.xlarge is not supported in af-south-1, eu-south-1, eu-west-3, me-south-1
diff --git a/tests/integration-tests/configs/common/common.yaml b/tests/integration-tests/configs/common/common.yaml
index 26dbe6f05b..ef41af097c 100644
--- a/tests/integration-tests/configs/common/common.yaml
+++ b/tests/integration-tests/configs/common/common.yaml
@@ -39,7 +39,7 @@ cli_commands:
     dimensions:
       - regions: ["ap-northeast-2"]
         instances: {{ common.INSTANCES_DEFAULT_X86 }}
-        oss: ["ubuntu1804"]
+        oss: ["ubuntu2004"]
         schedulers: ["slurm"]
 cloudwatch_logging:
   test_cloudwatch_logging.py::test_cloudwatch_logging:
@@ -60,7 +60,7 @@ cloudwatch_logging:
         schedulers: ["slurm"]
       - regions: ["ap-east-1"]
         instances: {{ common.INSTANCES_DEFAULT_X86 }}
-        oss: ["ubuntu1804", "centos7"]
+        oss: ["rhel8", "centos7"]
         schedulers: ["slurm"]
   test_compute_console_output_logging.py::test_console_output_with_monitoring_disabled:
     dimensions:
@@ -120,7 +120,7 @@ create:
     dimensions:
       - regions: ["eu-central-1"]
         instances: {{ common.INSTANCES_DEFAULT_X86 }}
-        oss: ["ubuntu1804"]  # os must be different from ubuntu2004 to test os validation logic when wrong os is provided
+        oss: ["rhel8"]  # os must be different from ubuntu2004 to test os validation logic when wrong os is provided
         schedulers: ["slurm"]
   test_create.py::test_create_wrong_pcluster_version:
     dimensions:
@@ -162,7 +162,7 @@ createami:
     dimensions:
       - regions: ["eu-west-3"]
         instances: {{ common.INSTANCES_DEFAULT_X86 }}
-        oss: ["ubuntu2004", "alinux2", "ubuntu1804"]
+        oss: ["ubuntu2004", "alinux2", "rhel8"]
   test_createami.py::test_kernel4_build_image_run_cluster:
     dimensions:
       - regions: ["eu-south-1"]
@@ -460,7 +460,7 @@ schedulers:
     dimensions:
       - regions: ["ap-east-1"]
         instances: {{ common.INSTANCES_DEFAULT_X86 }}
-        oss: ["ubuntu1804"]
+        oss: ["ubuntu2004"]
         schedulers: ["slurm"]
   test_slurm.py::test_slurm_memory_based_scheduling:
     dimensions:
@@ -580,7 +580,7 @@ storage:
     dimensions:
       - regions: ["us-west-1"]
         instances: {{ common.INSTANCES_DEFAULT_ARM }}
-        oss: ["ubuntu1804"]
+        oss: ["rhel8"]
         schedulers: ["slurm"]
   # EFS tests can be done in any region.
   test_efs.py::test_efs_compute_az:
@@ -637,7 +637,7 @@ storage:
     dimensions:
       - regions: ["us-east-2"]
         instances: {{ common.INSTANCES_DEFAULT_X86 }}
-        oss: ["ubuntu1804"]
+        oss: ["ubuntu2004"]
         schedulers: ["slurm"]
   test_ebs.py::test_ebs_single:
     dimensions:
@@ -653,7 +653,7 @@ storage:
         schedulers: ["slurm"]
       - regions: ["cn-northwest-1"]
         instances: {{ common.INSTANCES_DEFAULT_X86 }}
-        oss: ["ubuntu1804"]
+        oss: ["rhel8"]
         schedulers: ["slurm"]
   test_ebs.py::test_ebs_existing:
     dimensions:
diff --git a/tests/integration-tests/configs/installer.yaml b/tests/integration-tests/configs/installer.yaml
index c15be760aa..7a7d9ea188 100644
--- a/tests/integration-tests/configs/installer.yaml
+++ b/tests/integration-tests/configs/installer.yaml
@@ -6,5 +6,5 @@ test-suites:
       dimensions:
         - regions: [ "ap-northeast-2" ]
           instances: {{ common.INSTANCES_DEFAULT_X86 }}
-          oss: [ "ubuntu1804" ]
+          oss: [ "ubuntu2004" ]
           schedulers: [ "slurm" ]
diff --git a/tests/integration-tests/configs/new_instance_types.yaml b/tests/integration-tests/configs/new_instance_types.yaml
index 7794950ef3..c172efcb9a 100644
--- a/tests/integration-tests/configs/new_instance_types.yaml
+++ b/tests/integration-tests/configs/new_instance_types.yaml
@@ -77,7 +77,7 @@ test-suites:
       dimensions:
         - regions: {{ NEW_REGIONS }}
           instances: {{ NEW_INSTANCE_TYPES }}
-          oss: ["alinux2", "ubuntu1804", "ubuntu2004"]
+          oss: ["alinux2", "rhel8", "ubuntu2004"]
           schedulers: ["slurm"]
   configure:
     test_pcluster_configure.py::test_pcluster_configure:
@@ -91,7 +91,7 @@ test-suites:
       dimensions:
         - regions: {{ NEW_REGIONS }}
           instances: {{ NEW_INSTANCE_TYPES }}
-          oss: ["ubuntu1804"]
+          oss: ["ubuntu2004"]
           schedulers: ["slurm"]
 #     Useful for instances with multiple network interfaces
     test_multi_cidr.py::test_multi_cidr:
diff --git a/tests/integration-tests/configs/new_region.yaml b/tests/integration-tests/configs/new_region.yaml
index 87148df0de..279ef070b4 100644
--- a/tests/integration-tests/configs/new_region.yaml
+++ b/tests/integration-tests/configs/new_region.yaml
@@ -39,7 +39,7 @@ test-suites:
       dimensions:
         - regions: {{ NEW_REGION }}
           instances: {{ common.INSTANCES_DEFAULT_X86 }}
-          oss: ["ubuntu1804"]
+          oss: ["rhel8"]
           schedulers: ["slurm"]
   configure:
     test_pcluster_configure.py::test_pcluster_configure:
@@ -53,7 +53,7 @@ test-suites:
       dimensions:
         - regions: {{ NEW_REGION }}
           instances: {{ common.INSTANCES_DEFAULT_X86 }}
-          oss: ["ubuntu1804"]
+          oss: ["ubuntu2004"]
           schedulers: ["slurm"]
   update:
     test_update.py::test_update_slurm:
@@ -75,7 +75,7 @@ test-suites:
         # DCV on GPU enabled instance
         - regions: {{ NEW_REGION }}
           instances: ["g3.8xlarge"]
-          oss: ["ubuntu1804"]
+          oss: ["rhel8"]
           schedulers: ["slurm"]
         # DCV om non GPU enabled instance
         - regions: {{ NEW_REGION }}
@@ -108,7 +108,7 @@ test-suites:
       dimensions:
         - regions: {{ NEW_REGION }}
           instances: {{ common.INSTANCES_DEFAULT_X86 }}
-          oss: ["ubuntu1804"]
+          oss: ["ubuntu2004"]
           schedulers: ["slurm"]
     test_networking.py::test_public_network_topology:
       dimensions:
diff --git a/tests/integration-tests/conftest_markers.py b/tests/integration-tests/conftest_markers.py
index 06529ffa87..2532a7ac02 100644
--- a/tests/integration-tests/conftest_markers.py
+++ b/tests/integration-tests/conftest_markers.py
@@ -19,7 +19,6 @@
     ("eu-west-3", "c4.xlarge", "*", "*"),
     ("ap-east-1", "c4.xlarge", "*", "*"),
     ("*", "*", "centos7", "awsbatch"),
-    ("*", "*", "ubuntu1804", "awsbatch"),
     ("*", "*", "ubuntu2004", "awsbatch"),
     ("us-gov-east-1", "*", "c4.xlarge", "*"),
 ]
diff --git a/tests/integration-tests/tests/common/utils.py b/tests/integration-tests/tests/common/utils.py
index d6921eb6c4..c2bf996e18 100644
--- a/tests/integration-tests/tests/common/utils.py
+++ b/tests/integration-tests/tests/common/utils.py
@@ -33,10 +33,6 @@
     "alinux2": {"name": "amzn2-ami-kernel-5.10-hvm-*.*.*.*-*-gp2", "owners": ["amazon"]},
     # TODO: use marketplace AMI if possible
     "centos7": {"name": "CentOS 7.*", "owners": ["125523088429"], "includeDeprecated": True},
-    "ubuntu1804": {
-        "name": "ubuntu/images/hvm-ssd/ubuntu-bionic-18.04-*-server-*",
-        "owners": ["099720109477", "513442679011", "837727238323"],
-    },
     "ubuntu2004": {
         "name": "ubuntu/images/hvm-ssd/ubuntu-focal-20.04-*-server-*",
         "owners": ["099720109477"],
@@ -49,7 +45,6 @@
 OS_TO_REMARKABLE_AMI_NAME_OWNER_MAP = {
     "alinux2": {"name": "Deep Learning Base AMI (Amazon Linux 2)*", "owners": ["amazon"]},
     "centos7": {"name": "FPGA Developer AMI*", "owners": ["679593333241"]},
-    "ubuntu1804": {"name": "Deep Learning Base AMI (Ubuntu 18.04)*", "owners": ["amazon"]},
     "ubuntu2004": {"name": "Deep Learning AMI GPU CUDA * (Ubuntu 20.04)*", "owners": ["amazon"]},
     # Simple redhat8 to be able to build in remarkable test
     "rhel8": {"name": "RHEL-8.7*_HVM*", "owners": ["309956199498", "841258680906", "219670896067"]},
@@ -65,7 +60,6 @@
 OS_TO_PCLUSTER_AMI_NAME_OWNER_MAP = {
     "alinux2": {"name": "amzn2-hvm-*-*", "owners": PCLUSTER_AMI_OWNERS},
     "centos7": {"name": "centos7-hvm-x86_64-*", "owners": PCLUSTER_AMI_OWNERS},
-    "ubuntu1804": {"name": "ubuntu-1804-lts-hvm-*-*", "owners": PCLUSTER_AMI_OWNERS},
     "ubuntu2004": {"name": "ubuntu-2004-lts-hvm-*-*", "owners": PCLUSTER_AMI_OWNERS},
     "rhel8": {"name": "rhel8-hvm-*-*", "owners": PCLUSTER_AMI_OWNERS},
 }
diff --git a/tests/integration-tests/tests/create/test_create.py b/tests/integration-tests/tests/create/test_create.py
index d708ec4a15..03bf5b8141 100644
--- a/tests/integration-tests/tests/create/test_create.py
+++ b/tests/integration-tests/tests/create/test_create.py
@@ -29,7 +29,7 @@
 @pytest.mark.usefixtures("instance", "scheduler")
 def test_create_wrong_os(region, os, pcluster_config_reader, clusters_factory, architecture, request):
     """Test error message when os provide is different from the os of custom AMI"""
-    # ubuntu1804 is specified in the config file but an AMI of ubuntu2004 is provided
+    # rhel8 is specified in the config file but an AMI of ubuntu2004 is provided
     wrong_os = "ubuntu2004"
     logging.info("Asserting os fixture is different from wrong_os variable")
     assert_that(os != wrong_os).is_true()
diff --git a/tests/integration-tests/tests/createami/test_createami.py b/tests/integration-tests/tests/createami/test_createami.py
index bc7479a2f2..88f532aed8 100644
--- a/tests/integration-tests/tests/createami/test_createami.py
+++ b/tests/integration-tests/tests/createami/test_createami.py
@@ -443,7 +443,7 @@ def test_build_image_custom_components(
 ):
     """Test custom components and base AMI is ParallelCluster AMI"""
     # Custom script
-    custom_script_file = "custom_script_ubuntu.sh" if os in ["ubuntu1804", "ubuntu2004"] else "custom_script.sh"
+    custom_script_file = "custom_script_ubuntu.sh" if os in ["ubuntu2004"] else "custom_script.sh"
 
     # Create S3 bucket for pre install scripts, to remove epel package if it is installed
     bucket_name = s3_bucket_factory()
diff --git a/tests/integration-tests/tests/createami/test_createami/test_build_image_custom_components/image.config.yaml b/tests/integration-tests/tests/createami/test_createami/test_build_image_custom_components/image.config.yaml
index 9161291371..17a41711ac 100644
--- a/tests/integration-tests/tests/createami/test_createami/test_build_image_custom_components/image.config.yaml
+++ b/tests/integration-tests/tests/createami/test_createami/test_build_image_custom_components/image.config.yaml
@@ -3,7 +3,7 @@ Build:
   ParentImage: {{ parent_image }}
   Components:
     # Test arn custom component with combination (eu-west-1, m6g.xlarge, alinux2)
-    # Test script custom component with combination (ap-southeast-2, c5.xlarge, centos7) and (ap-southeast-2, c5.xlarge, ubuntu1804)
+    # Test script custom component with combination (ap-southeast-2, c5.xlarge, centos7) and (ap-southeast-2, c5.xlarge, ubuntu2004)
     {% if region == "eu-west-1" %}
     - Type: arn
       Value: arn:aws:imagebuilder:eu-west-1:aws:component/docker-ce-linux/1.0.0
diff --git a/tests/integration-tests/tests/efa/test_efa/test_efa/nccl_benchmarks/init_nccl_benchmarks.sh b/tests/integration-tests/tests/efa/test_efa/test_efa/nccl_benchmarks/init_nccl_benchmarks.sh
index 43c705149e..1b43c0b6c0 100644
--- a/tests/integration-tests/tests/efa/test_efa/test_efa/nccl_benchmarks/init_nccl_benchmarks.sh
+++ b/tests/integration-tests/tests/efa/test_efa/test_efa/nccl_benchmarks/init_nccl_benchmarks.sh
@@ -6,7 +6,6 @@ rm -rf /shared/${1}
 module load ${1}
 NCCL_BENCHMARKS_VERSION='2.10.0'
 NCCL_VERSION='2.7.8-1'
-ML_REPO_PKG='nvidia-machine-learning-repo-ubuntu1804_1.0.0-1_amd64.deb'
 OFI_NCCL_VERSION='1.1.1'
 MPI_HOME=$(which mpirun | awk -F '/bin' '{print $1}')
 NVCC_GENCODE="-gencode=arch=compute_80,code=sm_80" # Arch for NVIDIA A100
diff --git a/tests/integration-tests/utils.py b/tests/integration-tests/utils.py
index 3a4abc4548..8fb8c5ff6e 100644
--- a/tests/integration-tests/utils.py
+++ b/tests/integration-tests/utils.py
@@ -504,7 +504,6 @@ def get_username_for_os(os):
     usernames = {
         "alinux2": "ec2-user",
         "centos7": "centos",
-        "ubuntu1804": "ubuntu",
         "ubuntu2004": "ubuntu",
         "rhel8": "ec2-user",
     }
diff --git a/util/generate-ami-list.py b/util/generate-ami-list.py
index ffc4326733..174e845707 100644
--- a/util/generate-ami-list.py
+++ b/util/generate-ami-list.py
@@ -31,7 +31,6 @@
     [
         ("alinux2", "amzn2"),
         ("centos7", "centos7"),
-        ("ubuntu1804", "ubuntu-1804"),
         ("ubuntu2004", "ubuntu-2004"),
     ]
 )
@@ -67,7 +66,6 @@ def get_ami_list_from_file(regions, json_amis):
         "af-south-1": {
           "alinux2": "ami-xxx",
           "centos7": "UNSUPPORTED",
-          "ubuntu1804": "ami-zzz",
           "ubuntu2004": "ami-www"
         },
         "ap-east-1": {