{"id":84928,"date":"2021-02-16T23:17:39","date_gmt":"2021-02-16T20:17:39","guid":{"rendered":"https:\/\/computingforgeeks.com\/?p=84928"},"modified":"2023-08-21T13:17:54","modified_gmt":"2023-08-21T10:17:54","slug":"change-pids-limit-value-in-openshift","status":"publish","type":"post","link":"https:\/\/computingforgeeks.com\/change-pids-limit-value-in-openshift\/","title":{"rendered":"How to change pids_limit value in OpenShift 4.x"},"content":{"rendered":"\n

In OpenShift 4.x environment, each container running will be limited to the default maximum PID value of 1024<\/strong>. If there is a need to run applications with more than 1024<\/em> processes within one single container, the OpenShift Container Platform Cluster operator is required to adjust the default maximum PID value to a higher number.<\/p>\n\n\n\n

pids_limit<\/strong> is the maximum number of processes allowed in a container, and it can be viewed by running the command below in an OpenShift node:<\/p>\n\n\n\n

$ sudo crio-status config | grep <\/span>pid<\/mark>\npids_limit = 1024<\/code><\/pre>\n\n\n\n
In OpenShift, it is NOT recommended to change the value directly by editing crio.conf<\/strong> file:<\/p>\n\n\n\n
$ grep  pids_limit \/etc\/crio\/crio.conf<\/span>\npids_limit = 1024<\/mark><\/code><\/pre>\n\n\n\n
 It is recommended to follow the correct way that depends on the OCP version in use. I’m running OpenShift 4.4 and in this version, ContainerRuntimeConfig<\/code> custom resource was introduced. You can check KCS Article 5133191<\/a>.<\/p>\n\n\n\n
Create ContainerRuntimeConfig<\/em> custom resource for configuring cri-o pidsLimit<\/em><\/p>\n\n\n\n
cat <<EOF > custom-pidslimit.yaml\napiVersion: machineconfiguration.openshift.io\/v1\nkind: ContainerRuntimeConfig\nmetadata:\n name: custom-pidslimit\nspec:\n machineConfigPoolSelector:\n   matchLabels:\n     custom-crio: custom-pidslimit\n containerRuntimeConfig:\n   pidsLimit: 4096<\/mark>\nEOF<\/code><\/pre>\n\n\n\n
You can update the configuration file before applying:<\/p>\n\n\n\n
vim custom-pidslimit.yaml<\/code><\/pre>\n\n\n\n
Apply configuration:<\/p>\n\n\n\n
$ oc create -f custom-pidslimit.yaml<\/span>\ncontainerruntimeconfig.machineconfiguration.openshift.io\/custom-pidslimit created<\/code><\/pre>\n\n\n\n
Verify the resource has been created<\/p>\n\n\n\n
$ oc get ctrcfg<\/span>\nNAME               AGE\ncustom-pidslimit   44s<\/code><\/pre>\n\n\n\n
Once the custom resource is created, we need to roll out the pidslimit changes to all the worker nodes in the cluster.<\/p>\n\n\n\n
Let’s add custom-crio: custom-pidslimit under labels in the machineConfigPool config<\/p>\n\n\n\n
$ oc edit machineconfigpool worker<\/span>\napiVersion: machineconfiguration.openshift.io\/v1\nkind: MachineConfigPool\nmetadata:\n  creationTimestamp: \"2020-07-15T08:29:58Z\"\n  generation: 7\n  labels:\n    custom-crio: custom-pidslimit      #add this line<\/code><\/pre>\n\n\n\n
Check to ensure that a new 99-worker-XXX-containerruntime is created and that a new rendered worker is created:<\/p>\n\n\n\n
$ oc get machineconfigs | grep containerruntime<\/span>\n99-worker-261cdd8d-c387-4f61-b1ce-b9ab2d025f09-containerruntime   601c2285f497bf7c73d84737b9977a0e697cb86a   2.2.0             93s<\/code><\/pre>\n\n\n\n
The changes should now be rolled out to each node in the worker pool via that new rendered-worker machine config.<\/p>\n\n\n\n
You can verify by checking that the latest rendered-worker machine-config has been rolled out to the pools successfully:<\/p>\n\n\n\n
$ oc get mcp<\/span>\nNAME     CONFIG                                             UPDATED   UPDATING   DEGRADED   MACHINECOUNT   READYMACHINECOUNT   UPDATEDMACHINECOUNT   DEGRADEDMACHINECOUNT   AGE\nmaster   rendered-master-238bb9ffd94d526621cba8ee876c3ac8   True      False      False      5              5                   5                     0                      216d\nworker   rendered-worker-6c236aa19af4d88fa0acdbc8f6ff53f3   False     True       True       10             0                   0                     7                      216d<\/code><\/pre>\n\n\n\n
Once a worker node is rebooted you can login and confirm the current setting:<\/p>\n\n\n\n
$ oc debug node\/<\/span><workernode><\/span>\nsh-4.4# chroot \/host<\/span>\nsh-4.4# grep pids_limit \/etc\/crio\/crio.conf<\/span><\/code><\/pre>\n\n\n\n
I hope this short guide was helpful in changing the default value of pids_limit<\/strong> in your OpenShift 4.x cluster.<\/p>\n\n\n\n
Reference:<\/p>\n\n\n\n