pod 생애 주기 단계
※ terminating은 pod 생애 주기에 포함되지 않음
pending
클러스터 승인은 되었으나, 하나 이상의 컨테이너가 설정되지 않았고 아직 실행할 준비가 안된 상태
파드가 스케줄되기 이전까지의 시간뿐만 아니라 컨테이너 이미지를 다운로드하는 시간도 포함running
노드에 파드가 배치되었고, 컨테이너가 생성되고 구동까지 된 상태
적어도 하나의 컨테이너가 아직 실행 중이거나, 시작 또는 재시작 상태succeeded
파드의 컨테이너들이 성공적으로 종료된 상태failed
파드의 컨테이너 중 적어도 하나의 컨테이너가 실패로 종료된 상태unknown
파드 상태를 확인할 수 없는 상태이며, 노드와 통신 오류로 인해 발생
[root@master ~]# kubectl get pod -o wide --watch
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
web3 0/1 Pending 0 0s <none> <none> <none> <none>
web3 0/1 Pending 0 0s <none> node2 <none> <none>
web3 0/1 ContainerCreating 0 0s <none> node2 <none> <none>
web3 0/1 ContainerCreating 0 0s <none> node2 <none> <none>
web3 1/1 Running 0 3s 10.233.75.8 node2 <none> <none>
web3 1/1 Terminating 0 91s 10.233.75.8 node2 <none> <none>
web3 1/1 Terminating 0 91s 10.233.75.8 node2 <none> <none>
web3 0/1 Terminating 0 91s <none> node2 <none> <none>
web3 0/1 Terminating 0 92s 10.233.75.8 node2 <none> <none>
web3 0/1 Terminating 0 92s 10.233.75.8 node2 <none> <none>
web3 0/1 Terminating 0 92s 10.233.75.8 node2 <none> <none>컨테이너 상태
waiting : 컨테이너가 구동하기 위해 필요한 작업을 실행하고 있는 상태
running : 컨테이너가 구동 중인 상태
terminated : 컨테이너가 종료된 상태
liveness probe를 이용한 파드 실행 health-check(self-healing)
- pod 내 container로
httpget 요청을 통해 container의 health check tcpSocket80과 연결을 통해 health checkexeccommand를 통해 health check (웹서버가 아닌 경우 사용)
[root@master ~/kube/06/livenessProbe]# vi nginx-liveness-pod.yaml
[root@master ~/kube/06/livenessProbe]# cat nginx-liveness-pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: nginx-liveness-pod
spec:
containers:
- name: nginx-container
image: nginx
ports:
- containerPort: 80
protocol: TCP
livenessProbe:
httpGet:
path: /
port: 80
[root@master ~/kube/06/livenessProbe]# kubectl apply -f nginx-liveness-pod.yaml
pod/nginx-liveness-pod created
[root@master ~/kube/06/livenessProbe]# kubectl describe pod nginx-liveness-pod
Name: nginx-liveness-pod
Namespace: default
Priority: 0
Service Account: default
Node: node2/192.168.2.62
Start Time: Sat, 08 Mar 2025 16:50:06 +0900
Labels: <none>
Annotations: cni.projectcalico.org/containerID: 0ac2c38f44d84950abf9e8a46911944cd3fb4dbb92b36cfd6783ff61b1397243
cni.projectcalico.org/podIP: 10.233.75.9/32
cni.projectcalico.org/podIPs: 10.233.75.9/32
Status: Running
IP: 10.233.75.9
IPs:
IP: 10.233.75.9
Containers:
nginx-container:
Container ID: docker://a2cd09dab94e8e24f015b8893c3dbad00d164797d491672ffd546f305fec6841
Image: nginx
Image ID: docker-pullable://nginx@sha256:9d6b58feebd2dbd3c56ab5853333d627cc6e281011cfd6050fa4bcf2072c9496
Port: 80/TCP
Host Port: 0/TCP
State: Running
Started: Sat, 08 Mar 2025 16:50:09 +0900
Ready: True
Restart Count: 0
Liveness: http-get http://:80/ delay=0s timeout=1s period=10s #success=1 #failure=3
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-8m88p (ro)
[root@master ~/kube/06/livenessProbe]# kubectl logs nginx-liveness-pod -f
/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration
/docker-entrypoint.sh: Looking for shell scripts in /docker-entrypoint.d/
/docker-entrypoint.sh: Launching /docker-entrypoint.d/10-listen-on-ipv6-by-default.sh
10-listen-on-ipv6-by-default.sh: info: Getting the checksum of /etc/nginx/conf.d/default.conf
10-listen-on-ipv6-by-default.sh: info: Enabled listen on IPv6 in /etc/nginx/conf.d/default.conf
/docker-entrypoint.sh: Sourcing /docker-entrypoint.d/15-local-resolvers.envsh
/docker-entrypoint.sh: Launching /docker-entrypoint.d/20-envsubst-on-templates.sh
/docker-entrypoint.sh: Launching /docker-entrypoint.d/30-tune-worker-processes.sh
/docker-entrypoint.sh: Configuration complete; ready for start up
2025/03/08 07:50:09 [notice] 1#1: using the "epoll" event method
2025/03/08 07:50:09 [notice] 1#1: nginx/1.27.4
2025/03/08 07:50:09 [notice] 1#1: built by gcc 12.2.0 (Debian 12.2.0-14)
2025/03/08 07:50:09 [notice] 1#1: OS: Linux 5.14.0-452.el9.x86_64
2025/03/08 07:50:09 [notice] 1#1: getrlimit(RLIMIT_NOFILE): 1073741816:1073741816
2025/03/08 07:50:09 [notice] 1#1: start worker processes
2025/03/08 07:50:09 [notice] 1#1: start worker process 29
2025/03/08 07:50:09 [notice] 1#1: start worker process 30
2025/03/08 07:50:09 [notice] 1#1: start worker process 31
2025/03/08 07:50:09 [notice] 1#1: start worker process 32
192.168.2.62 - - [08/Mar/2025:07:50:16 +0000] "GET / HTTP/1.1" 200 615 "-" "kube-probe/1.27" "-"
192.168.2.62 - - [08/Mar/2025:07:50:26 +0000] "GET / HTTP/1.1" 200 615 "-" "kube-probe/1.27" "-"
192.168.2.62 - - [08/Mar/2025:07:50:36 +0000] "GET / HTTP/1.1" 200 615 "-" "kube-probe/1.27" "-"
192.168.2.62 - - [08/Mar/2025:07:50:46 +0000] "GET / HTTP/1.1" 200 615 "-" "kube-probe/1.27" "-"
192.168.2.62 - - [08/Mar/2025:07:50:56 +0000] "GET / HTTP/1.1" 200 615 "-" "kube-probe/1.27" "-"
192.168.2.62 - - [08/Mar/2025:07:51:06 +0000] "GET / HTTP/1.1" 200 615 "-" "kube-probe/1.27" "-"
192.168.2.62 - - [08/Mar/2025:07:51:16 +0000] "GET / HTTP/1.1" 200 615 "-" "kube-probe/1.27" "-"
192.168.2.62 - - [08/Mar/2025:07:51:26 +0000] "GET / HTTP/1.1" 200 615 "-" "kube-probe/1.27" "-"
실습 :: unhealthy-liveness-pod
[root@master ~/kube/06/unhealthy-liveness]# vi unhealty-liveness-pod.yaml
[root@master ~/kube/06/unhealthy-liveness]# cat unhealty-liveness-pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: unhealthy-liveness-pod
spec:
containers:
- name: unhealthy-container
image: smlinux/unhealthy
ports:
- containerPort: 8080
protocol: TCP
livenessProbe:
httpGet:
path: /
port: 8080
[root@master ~/kube/06/unhealthy-liveness]# kubectl apply -f unhealty-liveness-pod.yaml
pod/unhealthy-liveness-pod created
[root@master ~/kube/06/unhealthy-liveness]# kubectl describe pod unhealthy-liveness-pod
···
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 2m39s default-scheduler Successfully assigned default/unhealthy-liveness-pod to node2
Normal Pulled 2m36s kubelet Successfully pulled image "smlinux/unhealthy" in 2.366386176s (2.366391779s including waiting)
Warning Unhealthy 78s (x3 over 98s) kubelet Liveness probe failed: HTTP probe failed with statuscode: 500
Normal Killing 78s kubelet Container unhealthy-container failed liveness probe, will be restarted
Normal Pulling 48s (x2 over 2m38s) kubelet Pulling image "smlinux/unhealthy"
Normal Created 46s (x2 over 2m36s) kubelet Created container unhealthy-container
Normal Started 46s (x2 over 2m36s) kubelet Started container unhealthy-container
Normal Pulled 46s kubelet Successfully pulled image "smlinux/unhealthy" in 2.209982226s (2.210003245s including waiting)
[root@master ~/kube/06/unhealthy-liveness]# kubectl get pod unhealthy-liveness-pod
NAME READY STATUS RESTARTS AGE
unhealthy-liveness-pod 1/1 Running 1 (88s ago) 3m19s