Automation / Cloud / Infrastructre & Hardware / OpenShift

How to find the pod details from container in OpenShift

When we have issue with container and we are not sure which pod the container belongs to; we can find the pods details as below.

Use case : we have some zombie process running (defunct) but we are not sure which container is causing this zombie process.

Find the defunct processes

[root@node bin]# ps -ef |grep -v grep |grep -i defunct
1019710+  15222  15581  0 05:30 ?        00:00:00 [sh] 
1019710+  15618  15581  0 05:30 ?        00:00:00 [sh] 
1019710+  37360  15581  0 Sep23 ?        00:00:00 [sh] 
1019710+  37569  15581  0 Sep23 ?        00:00:00 [sh] 
1019710+  37806  15581  0 Sep23 ?        00:00:00 [sh] 
1019710+  37939  15581  0 Sep23 ?        00:00:00 [git] 

Find the docker image causing this zombies

We can use the systemd-cgls tool to find this; either run and search for the PID or grep for the PID.

[root@node bin]# systemd-cgls |grep -B4 15581
│   │   └─95146 /usr/bin/pod
│   ├─kubepods-burstable-poda3a903e7_b912_11e8_8c1f_40f2e91e547d.slice
│   │ ├─docker-24695bc78b0f3908786fe00616df5sc023c9acc535aa4f53a8c5a04c96f840611.scope
│   │ │ ├─15492 /usr/bin/dumb-init -- /usr/libexec/s2i/run
│   │ │ └─15581 /usr/java/jdk1.8.0_181-amd64/bin/java -XX:+UseParallelGC -XX:…

You can see the info in docker line.

Find the container ID

(usually first 12 digit of that docker line)

[root@node bin]# docker ps |grep 24695bc78b0f
24695bc78b0f        10.221.246.15:5000/delivery-prod/jenkins-as-a-service@sha256:9c3b04e78c201ba50459e4806a5106ac326ec92c46ef5381f46fd2b0ed812ac4                    "/usr/bin/dumb-init -"   8 days ago          Up 8 days                               k8s_jenkins-as-a-service-abcd_jenkins-as-a-service-abcd-18-qj76w_test_proj_a3a903e7-b912-11e8-8c1f-40f2e91e547d_0

We can read the project and pod information from above line by splitting last string by “_”.

• jenkins-as-a-service-abcd – application
• jenkins-as-a-service-abcd-18-qj76w – pod
• test_proj – project
• a3a903e7-b912-11e8-8c1f-40f2e91e547d – uid

Find and verify pod details from master

[root@master ~]# oc get pods|grep jenkins-as-a-service-abcd
and verify
[root@master ~]# oc get pod jenkins-as-a-service-abcd-18-qj76w -o=json

(Switch to respective project as you need)

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Tags: container · docker · How to find the pod details from container details · kubernetes · OpenShift · pod uid · Redhat OpenShift

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