Could not resolve host: yum.oracle.com; Unknown error

[ant0nk]

When I try to build Oracle Database image on CentOS 8 I get error:
https://yum.oracle.com/repo/OracleLinux/OL7/latest/x86_64/repodata/repomd.xml: [Errno 14] curl#6 - "Could not resolve host: yum.oracle.com; Unknown error".
But curl https://yum.oracle.com/repo/OracleLinux/OL7/latest/x86_64/repodata/repomd.xml at the same time works succesfully.
Full output:

[anton@localhost dockerfiles]$ sudo ./buildDockerImage.sh -e
[sudo] password for anton:
Checking Docker version.
Checking if required packages are present and valid...
LINUX.X64_193000_db_home.zip: OK
DOCKER info:
Client:
 Debug Mode: false
Server:
 Containers: 0
  Running: 0
  Paused: 0
  Stopped: 0
 Images: 19
 Server Version: 19.03.13
 Storage Driver: overlay2
  Backing Filesystem: xfs
  Supports d_type: true
  Native Overlay Diff: true
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: inactive
 Runtimes: runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 8fba4e9a7d01810a393d5d25a3621dc101981175
 runc version: dc9208a3303feef5b3839f4323d9beb36df0a9dd
 init version: fec3683
 Security Options:
  seccomp
   Profile: default
 Kernel Version: 4.18.0-193.el8.x86_64
 Operating System: CentOS Linux 8 (Core)
 OSType: linux
 Architecture: x86_64
 CPUs: 1
 Total Memory: 3.69GiB
 Name: localhost.localdomain
 ID: S2PR:RPMT:HUMQ:O7PH:OR5B:IIKY:GUXH:E2GP:RD3O:QQUB:56SY:CKJ6
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Live Restore Enabled: false
Building image 'oracle/database:19.3.0-ee' ...
Sending build context to Docker daemon   3.06GB
Step 1/22 : FROM oraclelinux:7-slim as base
 ---> dc7e50513559
Step 2/22 : LABEL "provider"="Oracle"                                                     "issues"="https://github.com/oracle/docker-images/issues"               "volume.data"="/opt/oracle/oradata"                                     "volume.setup.location1"="/opt/oracle/scripts/setup"                    "volume.setup.location2"="/docker-entrypoint-initdb.d/setup"            "volume.startup.location1"="/opt/oracle/scripts/startup"                "volume.startup.location2"="/docker-entrypoint-initdb.d/startup"        "port.listener"="1521"                                                  "port.oemexpress"="5500"
 ---> Running in e2e32ebeb0d6
Removing intermediate container e2e32ebeb0d6
 ---> ad736ac71636
Step 3/22 : ARG SLIMMING=true
 ---> Running in 3d4f21022945
Removing intermediate container 3d4f21022945
 ---> 7ccfd2a8c77f
Step 4/22 : ENV ORACLE_BASE=/opt/oracle     ORACLE_HOME=/opt/oracle/product/19c/dbhome_1     INSTALL_DIR=/opt/install     INSTALL_FILE_1="LINUX.X64_193000_db_home.zip"     INSTALL_RSP="db_inst.rsp"     CONFIG_RSP="dbca.rsp.tmpl"     PWD_FILE="setPassword.sh"     RUN_FILE="runOracle.sh"     START_FILE="startDB.sh"     CREATE_DB_FILE="createDB.sh"     SETUP_LINUX_FILE="setupLinuxEnv.sh"     CHECK_SPACE_FILE="checkSpace.sh"     CHECK_DB_FILE="checkDBStatus.sh"     USER_SCRIPTS_FILE="runUserScripts.sh"     INSTALL_DB_BINARIES_FILE="installDBBinaries.sh"     RELINK_BINARY_FILE="relinkOracleBinary.sh"     SLIMMING=$SLIMMING
 ---> Running in 0f94968e003f
Removing intermediate container 0f94968e003f
 ---> 171d97acb9fe
Step 5/22 : ENV PATH=$ORACLE_HOME/bin:$ORACLE_HOME/OPatch/:/usr/sbin:$PATH     LD_LIBRARY_PATH=$ORACLE_HOME/lib:/usr/lib     CLASSPATH=$ORACLE_HOME/jlib:$ORACLE_HOME/rdbms/jlib
 ---> Running in 4c32aa0aff47
Removing intermediate container 4c32aa0aff47
 ---> 5d30ca43aa8c
Step 6/22 : COPY $SETUP_LINUX_FILE $CHECK_SPACE_FILE $INSTALL_DIR/
 ---> 1a391d608f7e
Step 7/22 : COPY $RUN_FILE $START_FILE $CREATE_DB_FILE $CONFIG_RSP $PWD_FILE $CHECK_DB_FILE $USER_SCRIPTS_FILE $RELINK_BINARY_FILE $ORACLE_BASE/
 ---> e384f7fee7bb
Step 8/22 : RUN chmod ug+x $INSTALL_DIR/*.sh &&     sync &&     $INSTALL_DIR/$CHECK_SPACE_FILE &&     $INSTALL_DIR/$SETUP_LINUX_FILE &&     rm -rf $INSTALL_DIR
 ---> Running in 285c8a7c0794
Loaded plugins: ovl
https://yum.oracle.com/repo/OracleLinux/OL7/latest/x86_64/repodata/repomd.xml: [Errno 14] curl#6 - "Could not resolve host: yum.oracle.com; Unknown error"
Trying other mirror.
 One of the configured repositories failed (Oracle Linux 7Server Latest (x86_64)),
 and yum doesn't have enough cached data to continue. At this point the only
 safe thing yum can do is fail. There are a few ways to work "fix" this:
     1. Contact the upstream for the repository and get them to fix the problem.
     2. Reconfigure the baseurl/etc. for the repository, to point to a working
        upstream. This is most often useful if you are using a newer
        distribution release than is supported by the repository (and the
        packages for the previous distribution release still work).
     3. Run the command with the repository temporarily disabled
            yum --disablerepo=ol7_latest ...
     4. Disable the repository permanently, so yum won't use it by default. Yum
        will then just ignore the repository until you permanently enable it
        again or use --enablerepo for temporary usage:
            yum-config-manager --disable ol7_latest
        or
            subscription-manager repos --disable=ol7_latest
     5. Configure the failing repository to be skipped, if it is unavailable.
        Note that yum will try to contact the repo. when it runs most commands,
        so will have to try and fail each time (and thus. yum will be be much
        slower). If it is a very temporary problem though, this is often a nice
        compromise:
            yum-config-manager --save --setopt=ol7_latest.skip_if_unavailable=true
failure: repodata/repomd.xml from ol7_latest: [Errno 256] No more mirrors to try.
https://yum.oracle.com/repo/OracleLinux/OL7/latest/x86_64/repodata/repomd.xml: [Errno 14] curl#6 - "Could not resolve host: yum.oracle.com; Unknown error"
Removing intermediate container 285c8a7c0794
The command '/bin/sh -c chmod ug+x $INSTALL_DIR/*.sh &&     sync &&     $INSTALL_DIR/$CHECK_SPACE_FILE &&     $INSTALL_DIR/$SETUP_LINUX_FILE &&     rm -rf $INSTALL_DIR' returned a non-zero code: 1
ERROR: Oracle Database Docker Image was NOT successfully created.
ERROR: Check the output and correct any reported problems with the docker build operation.

[Djelibeybi]

This looks like an issue with the configuration of Docker on your CentOS 8 box. If you just run docker run --rm -it oraclelinux:7-slim on that box, does yum update work? If not, you will need to either configure a proxy (if one is required) or fix your networking.

[ant0nk]

This does not work either. But how is this possible if for example curl https://yum.oracle.com/repo/OracleLinux/OL7/latest/x86_64/repodata/repomd.xml works well?

[Djelibeybi]

Is that working inside the container? Or on the host?

[ant0nk]

yum update works on host (CentOS 8) but does not work in container suggested by you (oracle linux 7 slim).

[Djelibeybi]

You will need to work out why your container networking is broken. This is a CentOS/Docker issue, not an image issue.

[bmaupin]

@ant0nk Try adding this parameter to buildDockerImage.sh -o --network=host

e.g. /buildDockerImage.sh -e -o --network=host

[ant0nk]

@ant0nk Try adding this parameter to buildDockerImage.sh -o --network=host

e.g. /buildDockerImage.sh -e -o --network=host

Thank you. That worked.

[ant0nk]

Shouldn't this recommendation (-o --network=host) be added to the readme? Because by default docker creates internal network without access to host and external world, regardless of host OS.

[Djelibeybi]

Shouldn't this recommendation (-o --network=host) be added to the readme?

This doesn't happen on any other build of Docker though, so it's CentOS-specific. It's not needed for Docker on Oracle Linux, Windows or macOS. I would also recommend finding out what CentOS are doing to break the default Docker network instead of working around it by using the host network.

[cjbj]

@Djelibeybi what about adding it to the FAQ?

[finnjohnsen]

This doesn't happen on any other build of Docker though, so it's CentOS-specific.

I had to do the same in Ubuntu 21.10.

[alimhanna1991]

i've solved this issue by
$ dhclient
then
$ yum update

[ashrafulgit]

i've solved this issue by $ dhclient then $ yum update

It woked for me also. Thanks a lot.

[franmartosr]

@ant0nk Try adding this parameter to buildDockerImage.sh -o --network=host

e.g. /buildDockerImage.sh -e -o --network=host

That worked for me as well on Ubuntu 22.04, thanks a lot!