[RHPAM-4777] - Dynamic resources script is reading wrong container sy…

…s files on cgroupsv2 (#423) (#425)

Signed-off-by: Your Name <fspolti@redhat.com>
Co-authored-by: Filippe Spolti <filippespolti@gmail.com>

jboss/container/java/jvm/bash/artifacts/opt/jboss/container/java/jvm/container-limits

@@ -8,6 +8,19 @@
 #
 # This script is meant to be sourced.
 
+if [ "${SCRIPT_DEBUG}" = "true" ] ; then
+    set -x
+fi
+
+# query the resources based on cgroups version
+# cgroups v1 points to tmpfs
+# cgroups v2 points to cgroup2fs
+CGROUPS_VERSION="v1"
+tmp_fs=$(stat -fc %T /sys/fs/cgroup)
+if [ "${tmp_fs}" = "cgroup2fs" ]; then
+  CGROUPS_VERSION="v2"
+fi
+
 ceiling() {
   awk -vnumber="$1" -vdiv="$2" '
     function ceiling(x){
@@ -21,16 +34,36 @@ ceiling() {
 
 # Based on the cgroup limits, figure out the max number of core we should utilize
 core_limit() {
-  local cpu_period_file="/sys/fs/cgroup/cpu/cpu.cfs_period_us"
-  local cpu_quota_file="/sys/fs/cgroup/cpu/cpu.cfs_quota_us"
-  if [ -r "${cpu_period_file}" ]; then
-    local cpu_period="$(cat ${cpu_period_file})"
-
-    if [ -r "${cpu_quota_file}" ]; then
-      local cpu_quota="$(cat ${cpu_quota_file})"
-      # cfs_quota_us == -1 --> no restrictions
-      if [ "x$cpu_quota" != "x-1" ]; then
-        ceiling "$cpu_quota" "$cpu_period"
+  if [ "${CGROUPS_VERSION}" = "v1" ]; then
+    local cpu_period_file="/sys/fs/cgroup/cpu/cpu.cfs_period_us"
+    local cpu_quota_file="/sys/fs/cgroup/cpu/cpu.cfs_quota_us"
+    if [ -r "${cpu_period_file}" ]; then
+      local cpu_period="$(cat ${cpu_period_file})"
+      if [ -r "${cpu_quota_file}" ]; then
+        local cpu_quota="$(cat ${cpu_quota_file})"
+        # cfs_quota_us == -1 --> no restrictions
+        if [ "x$cpu_quota" != "x-1" ]; then
+          ceiling "$cpu_quota" "$cpu_period"
+        fi
+      fi
+    fi
+  else
+    # v2
+    # on cgroupsv2 the period and quota a queried from the same file
+    local cpu_max_file="/sys/fs/cgroup/cpu.max"
+    # when both are set we will have the following output:
+    # $MAX $PERIOD
+    # where the first number is the quota/max and the second is the period
+    # if the quota/max is not set then we will have only the period set:
+    # max 100000
+    if [ -r "${cpu_max_file}" ]; then
+      local cpu_max="$(cat ${cpu_max_file})"
+      if [ "x$cpu_max" != "x" ]; then
+        local cpu_quota="$(echo $cpu_max | awk '{print $1}')"
+        local cpu_period="$(echo $cpu_max | awk '{print $2}')"
+        if [ "$cpu_quota" != "max" ] && [ "x$cpu_period" != "x" ]; then
+          ceiling "$cpu_quota" "$cpu_period"
+        fi
       fi
     fi
   fi
@@ -41,14 +74,27 @@ max_unbounded() {
 }
 
 container_memory() {
-  # High number which is the max limit unit which memory is supposed to be
-  # unbounded. 
-  local mem_file="/sys/fs/cgroup/memory/memory.limit_in_bytes"
   local max_mem_unbounded="$(max_unbounded)"
-  if [ -r "${mem_file}" ]; then
-    local max_mem="$(cat ${mem_file})"
-    if [ ${max_mem} -lt ${max_mem_unbounded} ]; then
-      echo "${max_mem}"
+  # High number which is the max limit unit which memory is supposed to be unbounded.
+  if [ "${CGROUPS_VERSION}" = "v1" ]; then
+    local mem_file="/sys/fs/cgroup/memory/memory.limit_in_bytes"
+    if [ -r "${mem_file}" ]; then
+      local max_mem="$(cat ${mem_file})"
+      if [ ${max_mem} -lt ${max_mem_unbounded} ]; then
+        echo "${max_mem}"
+      fi
+    fi
+  else
+    # v2
+    local mem_file="/sys/fs/cgroup/memory.max"
+    if [ -r "${mem_file}" ]; then
+      local max_mem="$(cat ${mem_file})"
+      # if not set, it will contain only the string "max"
+      if [ "$max_mem" != "max" ]; then
+        if [ ${max_mem} -lt ${max_mem_unbounded} ]; then
+          echo "${max_mem}"
+        fi
+      fi
     fi
   fi
 }