[RHOCP4] openshift4 Pod 관리

RHOCP4 (openshift4)의 가장 최소 단위인 Pod 관리에 대해서 정리하였습니다.

본 내용도 노드 관리와 같이 지속적으로 추가 업데이트 예정입니다.

 

 

Pod 란 :

하나 이상의 컨테이너와 환경들로 구성되어 운영되는 단위를 말하며, 자체 내부 IP 주소와 Port가 할당됩니다.

 

 

1. Pod  확인

1.1 oc get pods -n openshift-multus

-> openshift-multus NS에 존재하는 Pod 목록 및 상태 확인

[root@bastion config]#oc get pods -n openshift-multus
NAME                                  READY   STATUS    RESTARTS   AGE
multus-6hqnq                          1/1     Running   0          3h47m
multus-additional-cni-plugins-7wrcc   1/1     Running   0          3h47m
multus-additional-cni-plugins-fqckw   1/1     Running   0          4h46m
multus-additional-cni-plugins-j9msn   1/1     Running   0          4h42m
multus-additional-cni-plugins-qwq8g   1/1     Running   0          4h38m
multus-admission-controller-d8sz9     2/2     Running   0          4h45m
multus-admission-controller-gxjj9     2/2     Running   0          4h38m
multus-admission-controller-hnlhp     2/2     Running   0          4h42m

 

 

1.2 oc get pods -n openshift-multus -o wide

-> pod의 상세 내용 보기, 추가로 IP와 어느 node에 배포되었는지 확인 가능

[root@bastion config]#oc get pods -n openshift-multus -o wide
NAME                                  READY   STATUS    RESTARTS   AGE     IP             NODE                    NOMINATED NODE   READINESS GATES
multus-6hqnq                          1/1     Running   0          3h49m   55.55.35.216   worker1.ocp-dc.hk.com   <none>           <none>
multus-additional-cni-plugins-7wrcc   1/1     Running   0          3h49m   55.55.35.216   worker1.ocp-dc.hk.com   <none>           <none>
multus-additional-cni-plugins-fqckw   1/1     Running   0          4h47m   55.55.35.211   master1.ocp-dc.hk.com   <none>           <none>
multus-additional-cni-plugins-j9msn   1/1     Running   0          4h44m   55.55.35.212   master2.ocp-dc.hk.com   <none>           <none>
multus-additional-cni-plugins-qwq8g   1/1     Running   0          4h40m   55.55.35.213   master3.ocp-dc.hk.com   <none>           <none>
multus-admission-controller-d8sz9     2/2     Running   0          4h47m   10.128.0.33    master1.ocp-dc.hk.com   <none>           <none>
multus-admission-controller-gxjj9     2/2     Running   0          4h40m   10.130.0.10    master3.ocp-dc.hk.com   <none>           <none>
multus-admission-controller-hnlhp     2/2     Running   0          4h44m   10.129.0.7     master2.ocp-dc.hk.com   <none>           <none>

 

 

1.3 oc get pods --all-namespaces

-> 모든 namespace (project)의 pod 정보 확인 가능 (route, service등등)

[root@bastion config]#oc get pods --all-namespaces
NAMESPACE                                          NAME                                                      READY   STATUS      RESTARTS   AGE
openshift-apiserver-operator                       openshift-apiserver-operator-79cb44596f-ckx7t             1/1     Running     2          4h53m
openshift-apiserver                                apiserver-6cd699c8b7-ph4mk                                2/2     Running     0          4h42m
openshift-apiserver                                apiserver-6cd699c8b7-wkqh7                                2/2     Running     0          4h41m
openshift-apiserver                                apiserver-6cd699c8b7-wvkh6                                2/2     Running     0          4h41m
openshift-authentication-operator                  authentication-operator-7f677f7559-wfd42                  1/1     Running     2          4h53m
openshift-authentication                           oauth-openshift-6d6b5fcfbb-mp7l8                          1/1     Running     0          4h33m
openshift-authentication                           oauth-openshift-6d6b5fcfbb-t7zcq                          1/1     Running     0          4h33m
openshift-authentication                           oauth-openshift-6d6b5fcfbb-wdfcj                          1/1     Running     0          4h33m
openshift-cloud-credential-operator                cloud-credential-operator-5ff6dbff57-4hgq4                2/2     Running     0          4h53m
openshift-cluster-machine-approver                 machine-approver-757975f664-ptdql                         2/2     Running     0          4h53m
openshift-cluster-node-tuning-operator             cluster-node-tuning-operator-7bb4c7584d-9fwlj             1/1     Running     0          4h53m
openshift-cluster-node-tuning-operator             tuned-289pj                                               1/1     Running     0          4h47m
openshift-cluster-node-tuning-operator             tuned-2ccq9                                               1/1     Running     0          4h46m
openshift-cluster-node-tuning-operator             tuned-9l6p2                                               1/1     Running     0          3h51m
openshift-cluster-node-tuning-operator             tuned-w98p7                                               1/1     Running     0          4h42m
openshift-cluster-samples-operator                 cluster-samples-operator-7c499478dc-zmgkn                 2/2     Running     0          4h41m

< 생략 >

 

 

2. Pod  세부 내용 확인

oc describe pod <pod name>

-> pod의 세부사항 확인 가능

[root@bastion config]#oc get pods -n openshift-sdn
NAME                   READY   STATUS    RESTARTS   AGE
sdn-controller-fjn25   1/1     Running   0          4h50m
sdn-controller-tj9c4   1/1     Running   0          4h46m
sdn-controller-vfnsq   1/1     Running   2          4h52m
sdn-g2n8c              2/2     Running   0          4h46m
sdn-q9kvt              2/2     Running   0          4h52m
sdn-wp9gg              2/2     Running   0          3h55m
sdn-xmhxx              2/2     Running   0          4h50m

[root@bastion config]#oc describe pod sdn-g2n8c -n openshift-sdn
Name:                 sdn-g2n8c
Namespace:            openshift-sdn
Priority:             2000001000
Priority Class Name:  system-node-critical
Node:                 master3.ocp-dc.hk.com/55.55.35.213
Start Time:           Tue, 09 Nov 2021 09:48:04 +0900
Labels:               app=sdn
                      component=network
                      
< 생략 >

 

 

3. Pod  로그 확인

oc logs <pod name>

-> pod 에러등이 발생했을 때 주로 사용

[root@bastion config]#oc logs oauth-openshift-6d6b5fcfbb-mp7l8
Copying system trust bundle
I1109 00:57:12.374789       1 dynamic_serving_content.go:111] Loaded a new cert/key pair for "serving-cert::/var/config/system/secrets/v4-0-config-system-serving-cert/tls.crt::/var/config/system/secrets/v4-0-config-system-serving-cert/tls.key"
I1109 00:57:12.375181       1 dynamic_serving_content.go:111] Loaded a new cert/key pair for "sni-serving-cert::/var/config/system/secrets/v4-0-config-system-router-certs/apps.ocp-dc.hk.com::/var/config/system/secrets/v4-0-config-system-router-certs/apps.ocp-dc.hk.com"
I1109 00:57:12.929620       1 requestheader_controller.go:244] Loaded a new request header values for RequestHeaderAuthRequestController

 

 

4. Pod  삭제

oc delete <pod name>

-> 특정 pod를 삭제합니다. deployment 배포 정책으로 생성한 파드의 경우에는 파드를 지워도 아래와 같이 다시 설정된 수 만큼의 파드를 유지하기 위해 재 생성합니다. 이러한 정책이 없이 배포하였다면 다시 생성되지 않고 지워집니다.

[root@bastion config]#oc get pods
NAME                               READY   STATUS    RESTARTS   AGE
oauth-openshift-6d6b5fcfbb-mp7l8   1/1     Running   0          4h43m
oauth-openshift-6d6b5fcfbb-t7zcq   1/1     Running   0          4h43m
oauth-openshift-6d6b5fcfbb-wdfcj   1/1     Running   0          4h43m


[root@bastion config]#oc delete pods oauth-openshift-6d6b5fcfbb-mp7l8
pod "oauth-openshift-6d6b5fcfbb-mp7l8" deleted


[root@bastion config]#oc get pods
NAME                               READY   STATUS    RESTARTS   AGE
oauth-openshift-6d6b5fcfbb-5f6t7   1/1     Running   0          37s
oauth-openshift-6d6b5fcfbb-t7zcq   1/1     Running   0          4h44m
oauth-openshift-6d6b5fcfbb-wdfcj   1/1     Running   0          4h44m

 

 

5. Pod  자원 사용량 확인

oc adm top pods

-> 각 pod들의 사용량을 확인할 수 있습니다.

[root@bastion config]#oc adm top pods
W1109 14:42:50.312988   46048 top_pod.go:140] Using json format to get metrics. Next release will switch to protocol-buffers, switch early by passing --use-protocol-buffers flag
NAME                               CPU(cores)   MEMORY(bytes)
oauth-openshift-6d6b5fcfbb-5f6t7   4m           22Mi
oauth-openshift-6d6b5fcfbb-t7zcq   2m           45Mi
oauth-openshift-6d6b5fcfbb-wdfcj   3m           42Mi