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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

[[email protected] 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.

[[email protected] 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)

[[email protected] bin]# docker ps |grep 24695bc78b0f
24695bc78b0f 10.221.246.15:5000/delivery-prod/[email protected]: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

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

(Switch to respective project as you need)

Disclaimer: The views expressed and the content shared are those of the author and do not reflect the views of the author’s employer or techbeatly platform.

Gineesh Madapparambath is the author of the book - 𝗔𝗻𝘀𝗶𝗯𝗹𝗲 𝗳𝗼𝗿 𝗥𝗲𝗮𝗹-𝗟𝗶𝗳𝗲 𝗔𝘂𝘁𝗼𝗺𝗮𝘁𝗶𝗼𝗻. He has worked as a Systems Engineer, Automation Specialist, and content author. His primary focus is on Ansible Automation, Containerisation (OpenShift & Kubernetes), and Infrastructure as Code (Terraform). (aka Gini Gangadharan - iamgini.com)

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