v2
imkunyoung@master-1:~/yaml/yaml/pods/probe$ nano exec-liveness.yamlexec-liveness.yaml
apiVersion: v1
kind: Pod
metadata:
labels:
test: liveness
name: liveness-exec
spec:
containers:
- name: liveness
image: registry.k8s.io/busybox
args:
- /bin/sh
- -c
- touch /tmp/healthy; sleep 30; rm -f /tmp/healthy; sleep 600
livenessProbe:
exec:
command:
- cat
- /tmp/healthy
initialDelaySeconds: 5
periodSeconds: 5imkunyoung@master-1:~/yaml/yaml/pods/probe$ kubectl create -f exec-liveness.yaml
pod/liveness-exec created
imkunyoung@master-1:~/yaml/yaml/pods/probe$ kubectl get pods
NAME READY STATUS RESTARTS AGE
liveness-exec 1/1 Running 0 14s
static-web-master-1 1/1 Running 0 3m9s
imkunyoung@master-1:~/yaml/yaml/pods/probe$ kubectl describe pod liveness-exec
Name: liveness-exec
Namespace: default
Priority: 0
Service Account: default
Node: worker-3/10.138.0.5
Start Time: Tue, 01 Aug 2023 01:40:15 +0000
Labels: test=liveness
Annotations: <none>
Status: Running
IP: 10.0.1.242
IPs:
IP: 10.0.1.242
Containers:
liveness:
Container ID: containerd://fb4f173d2f03f2cf5427ef0cbed2e8cd7d97ea528288ba0cd9f917bd7acc4dfc
Image: registry.k8s.io/busybox
Image ID: sha256:36a4dca0fe6fb2a5133dc11a6c8907a97aea122613fa3e98be033959a0821a1f
Port: <none>
Host Port: <none>
Args:
/bin/sh
-c
touch /tmp/healthy; sleep 30; rm -f /tmp/healthy; sleep 600
State: Running
Started: Tue, 01 Aug 2023 01:40:16 +0000
Ready: True
Restart Count: 0
Liveness: exec [cat /tmp/healthy] delay=5s timeout=1s period=5s #success=1 #failure=3
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-hnh4r (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
kube-api-access-hnh4r:
Type: Projected (a volume that contains injected data from multiple sources)
TokenExpirationSeconds: 3607
ConfigMapName: kube-root-ca.crt
ConfigMapOptional: <nil>
DownwardAPI: true
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 68s default-scheduler Successfully assigned default/liveness-exec to worker-3
Normal Pulling 67s kubelet Pulling image "registry.k8s.io/busybox"
Normal Pulled 67s kubelet Successfully pulled image "registry.k8s.io/busybox" in 159.294806ms (159.309066ms including waiting)
Normal Created 67s kubelet Created container liveness
Normal Started 67s kubelet Started container liveness
Warning Unhealthy 22s (x3 over 32s) kubelet Liveness probe failed: cat: can't open '/tmp/healthy': No such file or directory
Normal Killing 22s kubelet Container liveness failed liveness probe, will be restartedimkunyoung@master-1:~/yaml/yaml/pods/probe$ kubectl get pods
NAME READY STATUS RESTARTS AGE
liveness-exec 1/1 Running 3 (13s ago) 3m59s
static-web-master-1 1/1 Running 0 6m54s
imkunyoung@master-1:~/yaml/yaml/pods/probe$ kubectl describe pod liveness-exec
Name: liveness-exec
Namespace: default
Priority: 0
Service Account: default
Node: worker-3/10.138.0.5
Start Time: Tue, 01 Aug 2023 01:40:15 +0000
Labels: test=liveness
Annotations: <none>
Status: Running
IP: 10.0.1.242
IPs:
IP: 10.0.1.242
Containers:
liveness:
Container ID: containerd://6d69c6c00665015c49ce46f981272e61909774e72a8705baba69ddf677f9e97e
Image: registry.k8s.io/busybox
Image ID: sha256:36a4dca0fe6fb2a5133dc11a6c8907a97aea122613fa3e98be033959a0821a1f
Port: <none>
Host Port: <none>
Args:
/bin/sh
-c
touch /tmp/healthy; sleep 30; rm -f /tmp/healthy; sleep 600
State: Running
Started: Tue, 01 Aug 2023 01:46:31 +0000
Last State: Terminated
Reason: Error
Exit Code: 137
Started: Tue, 01 Aug 2023 01:45:16 +0000
Finished: Tue, 01 Aug 2023 01:46:31 +0000
Ready: True
Restart Count: 5
Liveness: exec [cat /tmp/healthy] delay=5s timeout=1s period=5s #success=1 #failure=3
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-hnh4r (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
kube-api-access-hnh4r:
Type: Projected (a volume that contains injected data from multiple sources)
TokenExpirationSeconds: 3607
ConfigMapName: kube-root-ca.crt
ConfigMapOptional: <nil>
DownwardAPI: true
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 7m31s default-scheduler Successfully assigned default/liveness-exec to worker-3
Normal Pulled 7m30s kubelet Successfully pulled image "registry.k8s.io/busybox" in 159.294806ms (159.309066ms including waiting)
Normal Pulled 6m15s kubelet Successfully pulled image "registry.k8s.io/busybox" in 151.603527ms (151.619746ms including waiting)
Normal Created 5m (x3 over 7m30s) kubelet Created container liveness
Normal Pulled 5m kubelet Successfully pulled image "registry.k8s.io/busybox" in 162.705096ms (162.721626ms including waiting)
Warning Unhealthy 4m15s (x9 over 6m55s) kubelet Liveness probe failed: cat: can't open '/tmp/healthy': No such file or directory
Normal Killing 4m15s (x3 over 6m45s) kubelet Container liveness failed liveness probe, will be restarted
Normal Pulling 3m45s (x4 over 7m30s) kubelet Pulling image "registry.k8s.io/busybox"
Normal Started 2m30s (x5 over 7m30s) kubelet Started container livenessimkunyoung@master-1:~/yaml/yaml/pods/probe$ nano http-liveness.yamlhttp-liveness.yaml
apiVersion: v1
kind: Pod
metadata:
labels:
test: liveness
name: liveness-http
spec:
containers:
- name: liveness
image: registry.k8s.io/liveness
args:
- /server
livenessProbe:
httpGet:
path: /healthz
port: 8080
httpHeaders:
- name: Custom-Header
value: Awesome
initialDelaySeconds: 3
periodSeconds: 3imkunyoung@master-1:~/yaml/yaml/pods/probe$ kubectl get pods
NAME READY STATUS RESTARTS AGE
liveness-exec 0/1 CrashLoopBackOff 7 (60s ago) 12m
liveness-http 1/1 Running 4 (34s ago) 107s
static-web-master-1 1/1 Running 0 15m
imkunyoung@master-1:~/yaml/yaml/pods/probe$ kubectl describe pod liveness-http
Name: liveness-http
Namespace: default
Priority: 0
Service Account: default
Node: worker-3/10.138.0.5
Start Time: Tue, 01 Aug 2023 01:50:59 +0000
Labels: test=liveness
Annotations: <none>
Status: Running
IP: 10.0.1.246
IPs:
IP: 10.0.1.246
Containers:
liveness:
Container ID: containerd://9816736d566ba73789828b858454e77a1b996af0d7af5cf2a581b22a205512ea
Image: registry.k8s.io/liveness
Image ID: sha256:554cfcf2aa85635c0b1ae9506f36f50118419766221651e70dfdc94631317b4d
Port: <none>
Host Port: <none>
Args:
/server
State: Running
Started: Tue, 01 Aug 2023 01:51:54 +0000
Last State: Terminated
Reason: Error
Exit Code: 2
Started: Tue, 01 Aug 2023 01:51:36 +0000
Finished: Tue, 01 Aug 2023 01:51:54 +0000
Ready: True
Restart Count: 3
Liveness: http-get http://:8080/healthz delay=3s timeout=1s period=3s #success=1 #failure=3
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-jjj8q (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
kube-api-access-jjj8q:
Type: Projected (a volume that contains injected data from multiple sources)
TokenExpirationSeconds: 3607
ConfigMapName: kube-root-ca.crt
ConfigMapOptional: <nil>
DownwardAPI: true
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 64s default-scheduler Successfully assigned default/liveness-http to worker-3
Normal Pulled 63s kubelet Successfully pulled image "registry.k8s.io/liveness" in 380.197977ms (380.221457ms including waiting)
Normal Pulled 45s kubelet Successfully pulled image "registry.k8s.io/liveness" in 148.690977ms (148.706358ms including waiting)
Normal Created 27s (x3 over 62s) kubelet Created container liveness
Normal Started 27s (x3 over 62s) kubelet Started container liveness
Normal Pulled 27s kubelet Successfully pulled image "registry.k8s.io/liveness" in 142.810947ms (142.822867ms including waiting)
Normal Pulling 9s (x4 over 63s) kubelet Pulling image "registry.k8s.io/liveness"
Warning Unhealthy 9s (x9 over 51s) kubelet Liveness probe failed: HTTP probe failed with statuscode: 500
Normal Killing 9s (x3 over 45s) kubelet Container liveness failed liveness probe, will be restartedtcp-liveness-readiness.yaml
apiVersion: v1
kind: Pod
metadata:
name: goproxy
labels:
app: goproxy
spec:
containers:
- name: goproxy
image: registry.k8s.io/goproxy:0.1
ports:
- containerPort: 8080
readinessProbe:
tcpSocket:
port: 8080
initialDelaySeconds: 5
periodSeconds: 10
livenessProbe:
tcpSocket:
port: 8080
initialDelaySeconds: 15
periodSeconds: 20kubectl apply -f https://k8s.io/examples/pods/probe/tcp-liveness-readiness.yamlimkunyoung@master-1:~/yaml/yaml/pods/probe$ kubectl describe pod goproxy
Name: goproxy
Namespace: default
Priority: 0
Service Account: default
Node: worker-4/10.138.0.6
Start Time: Tue, 01 Aug 2023 01:54:13 +0000
Labels: app=goproxy
Annotations: <none>
Status: Running
IP: 10.0.2.3
IPs:
IP: 10.0.2.3
Containers:
goproxy:
Container ID: containerd://09b7965990314d41b1ba9e44df893d86d5c822b7d79aaf67f1db5134d66dfbe6
Image: registry.k8s.io/goproxy:0.1
Image ID: registry.k8s.io/goproxy@sha256:5334c7ad43048e3538775cb09aaf184f5e8acf4b0ea60e3bc8f1d93c209865a5
Port: 8080/TCP
Host Port: 0/TCP
State: Running
Started: Tue, 01 Aug 2023 01:54:14 +0000
Ready: True
Restart Count: 0
Liveness: tcp-socket :8080 delay=15s timeout=1s period=20s #success=1 #failure=3
Readiness: tcp-socket :8080 delay=5s timeout=1s period=10s #success=1 #failure=3
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-kfjxl (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
kube-api-access-kfjxl:
Type: Projected (a volume that contains injected data from multiple sources)
TokenExpirationSeconds: 3607
ConfigMapName: kube-root-ca.crt
ConfigMapOptional: <nil>
DownwardAPI: true
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 71s default-scheduler Successfully assigned default/goproxy to worker-4
Normal Pulled 70s kubelet Container image "registry.k8s.io/goproxy:0.1" already present on machine
Normal Created 70s kubelet Created container goproxy
Normal Started 69s kubelet Started container goproxyv1
Liveness, Readiness, Startup 프로브
Liveness Probe
- 컨테이너 살았는지 판단하고 다시 시작하는 기능
- 컨테이너의 상태를 스스로 판단하여 교착 상태에 빠진 컨테이너를 재시작
- 버그가 생겨도 높은 가용성을 보임
Readiness Probe
- 포드가 준비된 상태에 있는지 확인하고 정상 서비스를 시작하는 기능
- 포드가 적절하게 준비되지 않은 경우 로드밸런싱을 하지 않음
Startup Probe
- 애플리케이션의 시작 시기 확인하여 가용성을 높이는 기능
- Liveness와 Readiness의 기능을 비활성화
exec-liveness.yaml
apiVersion: v1
kind: Pod
metadata:
labels:
test: liveness
name: liveness-exec
spec:
containers:
- name: liveness
image: k8s.gcr.io/busybox
args:
- /bin/sh
- -c
- touch /tmp/healthy; sleep 30; rm -rf /tmp/healthy; sleep 600
livenessProbe:
exec:
command:
- cat
- /tmp/healthy
initialDelaySeconds: 5
periodSeconds: 5kubectl describe pod liveness-exechttp-liveness.yaml
apiVersion: v1
kind: Pod
metadata:
labels:
test: liveness
name: liveness-http
spec:
containers:
- name: liveness
image: k8s.gcr.io/liveness
args:
- /server
livenessProbe:
httpGet:
path: /healthz
port: 8080
httpHeaders:
- name: Custom-Header
value: Awesome
initialDelaySeconds: 3
periodSeconds: 3tcp-liveness-readiness.yaml
apiVersion: v1
kind: Pod
metadata:
name: goproxy
labels:
app: goproxy
spec:
containers:
- name: goproxy
image: k8s.gcr.io/goproxy:0.1
ports:
- containerPort: 8080
readinessProbe:
tcpSocket:
port: 8080
initialDelaySeconds: 5
periodSeconds: 10
livenessProbe:
tcpSocket:
port: 8080
initialDelaySeconds: 15
periodSeconds: 20