Label & Selector
Table of contents
Label & Selector 에 관해 설명한다.
Labels
클러스트 내 오브젝트 생성 시의 메타 데이터로 설정한다. 키-값으로 구성되어 있으며 컨트롤러들이 관리할 파드를 선택하고 구분하기 위해 사용된다.
라벨이 서로 다른 yaml 4개를 준비한다.
root@master:~/labfile/label# ls
annotation.yaml label02.yaml label04.yaml
label01.yaml label03.yaml nodeselector.yaml
root@master:~/labfile/label# cat label01.yaml
apiVersion: v1
kind: Pod
metadata:
name: label-app01
labels:
app: nodejs
environment: develop
release: beta
spec:
containers:
- name: nodejs
image: takytaky/app:v1
ports:
- containerPort: 80
root@master:~/labfile/label#
root@master:~/labfile/label# cat label02.yaml
apiVersion: v1
kind: Pod
metadata:
name: label-app02
labels:
app: nodejs
environment: production
release: beta
spec:
containers:
- name: nodejs
image: takytaky/app:v1
ports:
- containerPort: 80
root@master:~/labfile/label#
root@master:~/labfile/label# cat label03.yaml
apiVersion: v1
kind: Pod
metadata:
name: label-app03
labels:
app: nodejs
environment: develop
release: stable
spec:
containers:
- name: nodejs
image: takytaky/app:v1
ports:
- containerPort: 80
root@master:~/labfile/label#
root@master:~/labfile/label# cat label04.yaml
apiVersion: v1
kind: Pod
metadata:
name: label-app04
labels:
app: nodejs
environment: production
release: stable
spec:
containers:
- name: nodejs
image: takytaky/app:v1
ports:
- containerPort: 80
root@master:~/labfile/label#
- 4개의 컨테이너를 생성한다.
kubectl apply -f label01.yaml -f label02.yaml -f label03.yaml -f label04.yaml
- pod 조회
kubectl get pods --show-labels
root@master:~/labfile/label# kubectl get pods --show-labels
NAME READY STATUS RESTARTS AGE LABELS
init-demo 1/1 Running 0 14h <none>
root@master:~/labfile/label#
root@master:~/labfile/label# kubectl apply -f label01.yaml -f label02.yaml -f la bel03.yaml -f label04.yaml
pod/label-app01 created
pod/label-app02 created
pod/label-app03 created
pod/label-app04 created
root@master:~/labfile/label#
// labels 조회
root@master:~/labfile/label# kubectl get pods --show-labels
NAME READY STATUS RESTARTS AGE LABELS
init-demo 1/1 Running 0 14h <none>
label-app01 1/1 Running 0 22s app=nodejs,environment=develop,release=beta
label-app02 1/1 Running 0 22s app=nodejs,environment=production,release=beta
label-app03 1/1 Running 0 21s app=nodejs,environment=develop,release=stable
label-app04 1/1 Running 0 21s app=nodejs,environment=production,release=stable
root@master:~/labfile/label#
// -l 옵션을 사용한 조회
root@master:~/labfile/label# kubectl get pods -l environment=production,release=stable --show-labels
NAME READY STATUS RESTARTS AGE LABELS
label-app04 1/1 Running 0 2m48s app=nodejs,environment=production,release=stable
root@master:~/labfile/label# kubectl get pods -l "app=nodejs,environment notin (develop)"
NAME READY STATUS RESTARTS AGE
label-app02 1/1 Running 0 3m
label-app04 1/1 Running 0 2m59s
root@master:~/labfile/label# kubectl get pods -l "release" --show-labels
NAME READY STATUS RESTARTS AGE LABELS
label-app01 1/1 Running 0 3m13s app=nodejs,environment=develop,release=beta
label-app02 1/1 Running 0 3m13s app=nodejs,environment=production,release=beta
label-app03 1/1 Running 0 3m12s app=nodejs,environment=develop,release=stable
label-app04 1/1 Running 0 3m12s app=nodejs,environment=production,release=stable
root@master:~/labfile/label#
NodeSelector
Label 을 통해서 노드를 선택할 수 있다.
spec > nodeSelector 정의in YAML
apiVersion: v1
kind: Pod
metadata:
name: nodeselector-pod
spec:
nodeSelector:
disk: ssd
- 라벨과 함께 노드 정보를 보여준다.
kubectl get nodes --show-labels
- worker1 노드에 disk=ssd 라벨를 추가한다.
kubectl label nodes worker1 disk=ssd
// worker1 에 disk=ssd 라벨 정의
root@master:~/labfile/label# kubectl label nodes worker1 disk=ssd
node/worker1 labeled
// 확인
root@master:~/labfile/label# kubectl get nodes --show-labels
NAME STATUS ROLES AGE VERSION LABELS
master Ready control-plane,master 2d10h v1.21.0 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=master,kubernetes.io/os=linux,node-role.kubernetes.io/control-plane=,node-role.kubernetes.io/master=,node.kubernetes.io/exclude-from-external-load-balancers=
worker1 Ready <none> 2d10h v1.21.0 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,disk=ssd,kubernetes.io/arch=amd64,kubernetes.io/hostname=worker1,kubernetes.io/os=linux
worker2 Ready <none> 2d10h v1.21.0 beta.kubernetes.io/arch=amd64,beta.kubernetes.io/os=linux,kubernetes.io/arch=amd64,kubernetes.io/hostname=worker2,kubernetes.io/os=linux
root@master:~/labfile/label#
root@master:~/labfile/label# cat nodeselector.yaml
apiVersion: v1
kind: Pod
metadata:
name: nodeselector-pod
spec:
nodeSelector:
disk: ssd
containers:
- name: nodeselector-pod
image: takytaky/app:v1
ports:
- containerPort: 80
root@master:~/labfile/label#
// 생성
root@master:~/labfile/label# kubectl apply -f nodeselector.yaml
pod/nodeselector-pod created
root@master:~/labfile/label# kubectl get pods
NAME READY STATUS RESTARTS AGE
nodeselector-pod 1/1 Running 0 24s
// disk=ssd 로 지정된 worker1 에서 생성됨 확인
root@master:~/labfile/label# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nodeselector-pod 1/1 Running 0 44s 172.16.235.136 worker1 <none> <none>
root@master:~/labfile/label#
annotation : 사용자가 오브젝트를 구분하고 필터링 하기 위한 용도이다.
파드 상세 조회
kubectl describe pod annotation-nodejs-o json 의미는 output 을 json 포맷으로 한다.
kubectl get pod annotation-nodejs -o json
- metadata.annotations 부분만 보여줄것
kubectl get pod annotation-nodejs -o jsonpath='{.metadata.annotations}'
root@master:~/labfile/label# cat annotation.yaml
apiVersion: v1
kind: Pod
metadata:
name: annotation-nodejs
labels:
app: nodejs
annotations:
manufacturer: "takytaky"
e-mail: "takytaky@example.com"
release-version: "v1"
spec:
containers:
- name: nodejs
image: takytaky/app:v1
ports:
- containerPort: 80
root@master:~/labfile/label#
root@master:~/labfile/label# kubectl apply -f annotation.yaml
pod/annotation-nodejs created
root@master:~/labfile/label#
// 파드 상세 조회
root@master:~/labfile/label# kubectl describe pod annotation-nodejs
Name: annotation-nodejs
Namespace: default
Priority: 0
Node: worker1/192.168.137.102
Start Time: Sun, 15 Jan 2023 00:10:46 +0000
Labels: app=nodejs
Annotations: cni.projectcalico.org/containerID: 3ab7969b5b88a8fc45a563d107daeb401ab1b6ddc0618ab3e04d3036ea8f9e7e
cni.projectcalico.org/podIP: 172.16.235.137/32
cni.projectcalico.org/podIPs: 172.16.235.137/32
e-mail: takytaky@example.com
manufacturer: takytaky
release-version: v1
Status: Running
IP: 172.16.235.137..
.. 중략
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 27s default-scheduler Successfully assigned default/annotation-nodejs to worker1
Normal Pulled 26s kubelet Container image "takytaky/app:v1" already present on machine
Normal Created 26s kubelet Created container nodejs
Normal Started 26s kubelet Started container nodejs
root@master:~/labfile/label#
root@master:~/labfile/label# ^C
root@master:~/labfile/label# kubectl get pod annotation-nodejs -o json
{
"apiVersion": "v1",
"kind": "Pod",
"metadata": {
"annotations": {
"cni.projectcalico.org/containerID": "3ab7969b5b88a8fc45a563d107daeb401ab1b6ddc0618ab3e04d3036ea8f9e7e",
"cni.projectcalico.org/podIP": "172.16.235.137/32",
"cni.projectcalico.org/podIPs": "172.16.235.137/32",
"e-mail": "takytaky@example.com",
"kubectl.kubernetes.io/last-applied-configuration": "{\"apiVersion\":\"v1\",\"kind\":\"Pod\",\"metadata\":{\"annotations\":{\"e-mail\":\"takytaky@example.com\",\"manufacturer\":\"takytaky\",\"release-version\":\"v1\"},\"labels\":{\"app\":\"nodejs\"},\"name\":\"annotation-nodejs\",\"namespace\":\"default\"},\"spec\":{\"containers\":[{\"image\":\"takytaky/app:v1\",\"name\":\"nodejs\",\"ports\":[{\"containerPort\":80}]}]}}\n",
"manufacturer": "takytaky",
"release-version": "v1"
},
"creationTimestamp": "2023-01-15T00:10:46Z",
"labels": {
"app": "nodejs"
},
"name": "annotation-nodejs",
"namespace": "default",
"resourceVersion": "24929",
"uid": "9283cd0a-907c-4e57-bb06-c5f01934d36e"
},
"spec": {
"containers": [
{
"image": "takytaky/app:v1",
"imagePullPolicy": "IfNotPresent",
"name": "nodejs",
"ports": [
{
"containerPort": 80,
"protocol": "TCP"
}
],
"resources": {},
"terminationMessagePath": "/dev/termination-log",
"terminationMessagePolicy": "File",
"volumeMounts": [
{
"mountPath": "/var/run/secrets/kubernetes.io/serviceaccount",
"name": "kube-api-access-n2bwn",
"readOnly": true
}
]
}
],
"dnsPolicy": "ClusterFirst",
"enableServiceLinks": true,
"nodeName": "worker1",
"preemptionPolicy": "PreemptLowerPriority",
"priority": 0,
"restartPolicy": "Always",
"schedulerName": "default-scheduler",
"securityContext": {},
"serviceAccount": "default",
"serviceAccountName": "default",
"terminationGracePeriodSeconds": 30,
"tolerations": [
{
"effect": "NoExecute",
"key": "node.kubernetes.io/not-ready",
"operator": "Exists",
"tolerationSeconds": 300
},
{
"effect": "NoExecute",
"key": "node.kubernetes.io/unreachable",
"operator": "Exists",
"tolerationSeconds": 300
}
],
"volumes": [
{
"name": "kube-api-access-n2bwn",
"projected": {
"defaultMode": 420,
"sources": [
{
"serviceAccountToken": {
"expirationSeconds": 3607,
"path": "token"
}
},
{
"configMap": {
"items": [
{
"key": "ca.crt",
"path": "ca.crt"
}
],
"name": "kube-root-ca.crt"
}
},
{
"downwardAPI": {
"items": [
{
"fieldRef": {
"apiVersion": "v1",
"fieldPath": "metadata.namespace"
},
"path": "namespace"
}
]
}
}
]
}
}
]
},
"status": {
"conditions": [
{
"lastProbeTime": null,
"lastTransitionTime": "2023-01-15T00:10:46Z",
"status": "True",
"type": "Initialized"
},
{
"lastProbeTime": null,
"lastTransitionTime": "2023-01-15T00:10:48Z",
"status": "True",
"type": "Ready"
},
{
"lastProbeTime": null,
"lastTransitionTime": "2023-01-15T00:10:48Z",
"status": "True",
"type": "ContainersReady"
},
{
"lastProbeTime": null,
"lastTransitionTime": "2023-01-15T00:10:46Z",
"status": "True",
"type": "PodScheduled"
}
],
"containerStatuses": [
{
"containerID": "docker://ff1ca04c7800af5f0c600aeff6d6a8131761cf826ea9e5a1e82c673011c82372",
"image": "takytaky/app:v1",
"imageID": "docker-pullable://takytaky/app@sha256:a0893a44ecbc0c74e022175caa64748077ed8a6502c4e35516df2797fc530804",
"lastState": {},
"name": "nodejs",
"ready": true,
"restartCount": 0,
"started": true,
"state": {
"running": {
"startedAt": "2023-01-15T00:10:48Z"
}
}
}
],
"hostIP": "192.168.137.102",
"phase": "Running",
"podIP": "172.16.235.137",
"podIPs": [
{
"ip": "172.16.235.137"
}
],
"qosClass": "BestEffort",
"startTime": "2023-01-15T00:10:46Z"
}
}
root@master:~/labfile/label# ^C
// metadata.annotations 부분만 보여줄것
root@master:~/labfile/label# kubectl get pod annotation-nodejs -o jsonpath='{.metadata.annotations}'
{"cni.projectcalico.org/containerID":"3ab7969b5b88a8fc45a563d107daeb401ab1b6ddc0618ab3e04d3036ea8f9e7e","cni.projectcalico.org/podIP":"172.16.235.137/32","cni.projectcalico.org/podIPs":"172.16.235.137/32","e-mail":"takytaky@example.com","kubectl.kubernetes.io/last-applied-configuration":"{\"apiVersion\":\"v1\",\"kind\":\"Pod\",\"metadata\":{\"annotations\":{\"e-mail\":\"takytaky@example.com\",\"manufacturer\":\"takytaky\",\"release-version\":\"v1\"},\"labels\":{\"app\":\"nodejs\"},\"name\":\"annotation-nodejs\",\"namespace\":\"default\"},\"spec\":{\"containers\":[{\"image\":\"takytaky/app:v1\",\"name\":\"nodejs\",\"ports\":[{\"containerPort\":80}]}]}}\n","manufacturer":"takytaky","release-version":"v1"}root@master:~/labfile/label#
root@master:~/labfile/label# ^C
root@master:~/labfile/label#
root@master:~/labfile/label# apt install -y jq
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
libjq1 libonig4
The following NEW packages will be installed:
jq libjq1 libonig4
0 upgraded, 3 newly installed, 0 to remove and 87 not upgraded.
Need to get 276 kB of archives.
After this operation, 930 kB of additional disk space will be used.
Get:1 http://kr.archive.ubuntu.com/ubuntu bionic/universe amd64 libonig4 amd64 6.7.0-1 [119 kB]
Get:2 http://kr.archive.ubuntu.com/ubuntu bionic/universe amd64 libjq1 amd64 1.5+dfsg-2 [111 kB]
Get:3 http://kr.archive.ubuntu.com/ubuntu bionic/universe amd64 jq amd64 1.5+dfsg-2 [45.6 kB]
Fetched 276 kB in 2s (139 kB/s)
Selecting previously unselected package libonig4:amd64.
(Reading database ... 173940 files and directories currently installed.)
Preparing to unpack .../libonig4_6.7.0-1_amd64.deb ...
Unpacking libonig4:amd64 (6.7.0-1) ...
Selecting previously unselected package libjq1:amd64.
Preparing to unpack .../libjq1_1.5+dfsg-2_amd64.deb ...
Unpacking libjq1:amd64 (1.5+dfsg-2) ...
Selecting previously unselected package jq.
Preparing to unpack .../jq_1.5+dfsg-2_amd64.deb ...
Unpacking jq (1.5+dfsg-2) ...
Setting up libonig4:amd64 (6.7.0-1) ...
Setting up libjq1:amd64 (1.5+dfsg-2) ...
Setting up jq (1.5+dfsg-2) ...
Processing triggers for man-db (2.8.3-2ubuntu0.1) ...
Processing triggers for libc-bin (2.27-3ubuntu1.5) ...
root@master:~/labfile/label# kubectl get pod annotation-nodejs -o jsonpath='{.metadata.annotations}' | jq
{
"cni.projectcalico.org/containerID": "3ab7969b5b88a8fc45a563d107daeb401ab1b6ddc0618ab3e04d3036ea8f9e7e",
"cni.projectcalico.org/podIP": "172.16.235.137/32",
"cni.projectcalico.org/podIPs": "172.16.235.137/32",
"e-mail": "takytaky@example.com",
"kubectl.kubernetes.io/last-applied-configuration": "{\"apiVersion\":\"v1\",\"kind\":\"Pod\",\"metadata\":{\"annotations\":{\"e-mail\":\"takytaky@example.com\",\"manufacturer\":\"takytaky\",\"release-version\":\"v1\"},\"labels\":{\"app\":\"nodejs\"},\"name\":\"annotation-nodejs\",\"namespace\":\"default\"},\"spec\":{\"containers\":[{\"image\":\"takytaky/app:v1\",\"name\":\"nodejs\",\"ports\":[{\"containerPort\":80}]}]}}\n",
"manufacturer": "takytaky",
"release-version": "v1"
}
jq 사용법
json 포맷에서의 색깔을 구분하여 보여준다.
# apt install -y jq설치 후 아래와 같이 jq 옵션을 추가한다.# kubectl get pod annotation-nodejs -o jsonpath='{.metadata.annotations}' | jq