configMap
ConfigMap : 许多应用程序会从 配置文件 、 命令行参数 或 环境变量 中读取配置信息。
ConfigMap API : 给我们提供了向容器中注入配置信息的机制，可以被用来保存单个属性，也可以用来保存整个配置文件或者 JSON 二进制大对象
configmap 注入方式有两种
使用目录创建
1 | $ mkdir configMap |
--from-file 指定目录下的所有文件都会被用在 ConfigMap 里面创建一个键值对， 键的名字就是文件名，值就是文件的内容
使用文件创建
只要指定为一个文件就可以从单个文件中创建 ConfigMap1
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37[root@k8s01 storage]# kubectl create configmap game-config-2 --from-file=configMap/game.properties --from-file=configMap/ui.properties
configmap/game-config-2 created
[root@k8s01 storage]# kubectl get configmaps game-config-2 -o yaml
apiVersion: v1
data:
game.properties: |
enemies=aliens
lives=3
enemies.cheat=true
enemies.cheat.level=noGoodRotten
secret.code.passphrase=UUDDLRLRBABAS
secret.code.allowed=true
secret.code.lives=30
ui.properties: |
color.good=purple
color.bad=yellow
allow.textmode=true
how.nice.to.look=fairlyNice
kind: ConfigMap
metadata:
creationTimestamp: "2020-08-27T15:59:05Z"
managedFields:
- apiVersion: v1
fieldsType: FieldsV1
fieldsV1:
f:data:
.: {}
f:game.properties: {}
f:ui.properties: {}
manager: kubectl
operation: Update
time: "2020-08-27T15:59:05Z"
name: game-config-2
namespace: default
resourceVersion: "235477"
selfLink: /api/v1/namespaces/default/configmaps/game-config-2
uid: c283cbf9-1eeb-49d8-8a1e-999099f4e97f
--from-file 这个参数可以使用多次，你可以使用两次分别指定上个实例中的那两个配置文件，效果就跟指定整个目录是一样的
使用字面值创建
使用文字值创建，利用--from-literal 参数传递配置信息，该参数可以使用多次，格式如下1
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41[root@k8s01 storage]# kubectl create configmap special-config --from-literal=special.how=very --from-literal=special.type=charm
configmap/special-config created
[root@k8s01 storage]# kubectl get configmaps special-config -o yaml
apiVersion: v1
data:
special.how: very
special.type: charm
kind: ConfigMap
metadata:
creationTimestamp: "2020-08-27T16:00:02Z"
managedFields:
- apiVersion: v1
fieldsType: FieldsV1
fieldsV1:
f:data:
.: {}
f:special.how: {}
f:special.type: {}
manager: kubectl
operation: Update
time: "2020-08-27T16:00:02Z"
name: special-config
namespace: default
resourceVersion: "235621"
selfLink: /api/v1/namespaces/default/configmaps/special-config
uid: 7ab83245-87dc-41eb-be95-584d68ed259e
[root@k8s01 storage]# kubectl describe cm special-config
Name: special-config
Namespace: default
Labels: <none>
Annotations: <none>
Data
====
special.how:
----
very
special.type:
----
charm
Events: <none>
1 | [root@k8s01 storage]# kubectl delete cm --all |
Pod 中使用 ConfigMap
使用 ConfigMap 来替代环境变量
special-config.yaml1
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8apiVersion: v1
kind: ConfigMap
metadata:
name: special-config
namespace: default
data:
special.how: very
special.type: charm
env-config.yaml1
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7apiVersion: v1
kind: ConfigMap
metadata:
name: env-config
namespace: default
data:
log_level: INFO
test-pod01.yaml1
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24apiVersion: v1
kind: Pod
metadata:
name: test-pod01
spec:
containers:
- name: test-container
image: nginx:1.7.9
command: ["/bin/sh","-c","env"]
env:
- name: SPECIAL_LEVEL_KEY
valueFrom:
configMapKeyRef:
name: special-config
key: special.how
- name: SPECIAL_TYPE_KEY
valueFrom:
configMapKeyRef:
name: special-config
key: special.type
envFrom:
- configMapRef:
name: env-config
restartPolicy: Never
1 | [root@k8s01 storage]# kubectl apply -f special-config.yaml |
通过环境变量引入：使用 envfrom
用 ConfigMap 设置命令行参数
test-pod02.yaml1
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21apiVersion: v1
kind: Pod
metadata:
name: test-pod02
spec:
containers:
- name: test-container
image: nginx:1.7.9
command: ["/bin/sh","-c","echo $(SPECIAL_LEVEL_KEY) $(SPECIAL_TYPE_KEY)"]
env:
- name: SPECIAL_LEVEL_KEY
valueFrom:
configMapKeyRef:
name: special-config
key: special.how
- name: SPECIAL_TYPE_KEY
valueFrom:
configMapKeyRef:
name: special-config
key: special.type
restartPolicy: Never
1 | [root@k8s01 storage]# kubectl apply -f test-pod02.yaml |
通过数据卷插件使用ConfigMap
在数据卷里面使用这个 ConfigMap，有不同的选项。最基本的就是将文件填入数据卷，在这个文件中，键就是文件名，键值就是文件内容
test_pod03.yaml1
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17apiVersion: v1
kind: Pod
metadata:
name: test-pod03
spec:
containers:
- name: test-container
image: nginx:1.7.9
command: ["/bin/sh","-c","sleep 600s"]
volumeMounts:
- name: config-volume
mountPath: /etc/config
volumes:
- name: config-volume
configMap:
name: special-config
restartPolicy: Never
1 | [root@k8s01 storage]# kubectl exec test-pod03 -it -- /bin/bash |
ConfigMap 的热更新
test04.yaml1
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34apiVersion: v1
kind: ConfigMap
metadata:
name: log-config
namespace: default
data:
log_level: INFO
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: my-nginx-test
spec:
replicas: 1
selector:
matchLabels:
run: my-nginx
template:
metadata:
labels:
run: my-nginx
spec:
containers:
- name: my-nginx
image: nginx:1.7.9
ports:
- containerPort: 80
volumeMounts:
- name: config-volume
mountPath: /etc/config
volumes:
- name: config-volume
configMap:
name: log-config
1 | [root@k8s01 storage]# kubectl get pods -l run=my-nginx -o=name|cut -d "/" -f2 |
修改 ConfigMap1
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6[root@k8s01 storage]# kubectl edit configmap log-config # 修改log_level的值为DEBUG等待大概 10 秒钟时间，再次查看环境变量的值
configmap/log-config edited
[root@k8s01 storage]# kubectl exec `kubectl get pods -l run=my-nginx -o=name|cut -d "/" -f2` -it -- cat /etc/config/log_level
INFO # 刚开始没变
[root@k8s01 storage]# kubectl exec `kubectl get pods -l run=my-nginx -o=name|cut -d "/" -f2` -it -- cat /etc/config/log_level
DEBUG # 后来变成 DEBUG
ConfigMap 更新后滚动更新 Pod
更新 ConfigMap 目前并不会触发相关 Pod 的滚动更新，可以通过修改 pod annotations 的方式强制触发滚动更新1
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84[root@k8s01 storage]# kubectl describe deployment my-nginx-test
Name: my-nginx-test
Namespace: default
CreationTimestamp: Thu, 27 Aug 2020 13:07:56 -0400
Labels: <none>
Annotations: deployment.kubernetes.io/revision: 1
Selector: run=my-nginx
Replicas: 1 desired | 1 updated | 1 total | 1 available | 0 unavailable
StrategyType: RollingUpdate
MinReadySeconds: 0
RollingUpdateStrategy: 25% max unavailable, 25% max surge
Pod Template:
Labels: run=my-nginx
Containers:
my-nginx:
Image: nginx:1.7.9
Port: 80/TCP
Host Port: 0/TCP
Environment: <none>
Mounts:
/etc/config from config-volume (rw)
Volumes:
config-volume:
Type: ConfigMap (a volume populated by a ConfigMap)
Name: log-config
Optional: false
Conditions:
Type Status Reason
---- ------ ------
Available True MinimumReplicasAvailable
Progressing True NewReplicaSetAvailable
OldReplicaSets: <none>
NewReplicaSet: my-nginx-test-59bf4fc6f8 (1/1 replicas created)
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ScalingReplicaSet 37s deployment-controller Scaled up replica set my-nginx-test-59bf4fc6f8 to 1
[root@k8s01 storage]# kubectl patch deployment my-nginx-test --patch '{"spec": {"template": {"metadata": {"annotations":{"version/config": "20200826" }}}}}'
deployment.apps/my-nginx-test patched
[root@k8s01 storage]# kubectl describe deployment my-nginx-test
Name: my-nginx-test
Namespace: default
CreationTimestamp: Thu, 27 Aug 2020 12:50:33 -0400
Labels: <none>
Annotations: deployment.kubernetes.io/revision: 2
Selector: run=my-nginx
Replicas: 1 desired | 1 updated | 1 total | 1 available | 0 unavailable
StrategyType: RollingUpdate
MinReadySeconds: 0
RollingUpdateStrategy: 25% max unavailable, 25% max surge
Pod Template:
Labels: run=my-nginx
Annotations: version/config: 20200826
Containers:
my-nginx:
Image: nginx:1.7.9
Port: 80/TCP
Host Port: 0/TCP
Environment: <none>
Mounts:
/etc/config from config-volume (rw)
Volumes:
config-volume:
Type: ConfigMap (a volume populated by a ConfigMap)
Name: log-config
Optional: false
Conditions:
Type Status Reason
---- ------ ------
Available True MinimumReplicasAvailable
Progressing True NewReplicaSetAvailable
OldReplicaSets: <none>
NewReplicaSet: my-nginx-test-74f5cf4498 (1/1 replicas created)
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ScalingReplicaSet 15m deployment-controller Scaled up replica set my-nginx-test-59bf4fc6f8 to 1
Normal ScalingReplicaSet 3m21s deployment-controller Scaled up replica set my-nginx-test-74f5cf4498 to 1
Normal ScalingReplicaSet 3m18s deployment-controller Scaled down replica set my-nginx-test-59bf4fc6f8 to 0
这个例子里我们在 .spec.template.metadata.annotations 中添加 version/config，每次通过修改 version/config 来触发滚动更新
！！！更新 ConfigMap 后：
- 使用该 ConfigMap 挂载的 Env 不会同步更新
- 使用该 ConfigMap 挂载的 Volume 中的数据需要一段时间（实测大概10秒）才能同步更新
DownwardAPI
DownwardAPI 可以获取 Pod 对象中定义的字段，比如 Pod 的标签（Labels）、Pod 的 IP 地址及 Pod 所在的命名空间（namespace）等。
Downward API 有两种使用方法，既支持环境变量注入，也支持通过 Volume 挂载。
DownwardAPI 使用
1 | [root@k8s01 stroage]# cat downwardapi-volume-demo.yaml |
查看1
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34[root@k8s01 stroage]# kubectl apply -f downwardapi-volume-demo.yaml
pod/downwardapi-volume-demo created
[root@k8s01 stroage]# kubectl logs -n demo -f downwardapi-volume-demo
cluster="downward-api-test-cluster1"
rack="rack-123"
zone="us-east-coast"
annotation1="345"
annotation2="456"
kubectl.kubernetes.io/last-applied-configuration="{\"apiVersion\":\"v1\",\"kind\":\"Pod\",\"metadata\":{\"annotations\":{\"annotation1\":\"345\",\"annotation2\":\"456\"},\"labels\":{\"cluster\":\"downward-api-test-cluster1\",\"rack\":\"rack-123\",\"zone\":\"us-east-coast\"},\"name\":\"downwardapi-volume-demo\",\"namespace\":\"demo\"},\"spec\":{\"containers\":[{\"args\":[\"while true; do if [[ -e /etc/podinfo/labels ]]; then echo -en '\\\\n\\\\n'; cat /etc/podinfo/labels; fi; if [[ -e /etc/podinfo/annotations ]]; then echo -en '\\\\n\\\\n'; cat /etc/podinfo/annotations; fi; sleep 5; done;\"],\"command\":[\"sh\",\"-c\"],\"image\":\"busybox:1.28\",\"name\":\"volume-test-container\",\"volumeMounts\":[{\"mountPath\":\"/etc/podinfo\",\"name\":\"podinfo\"}]}],\"volumes\":[{\"downwardAPI\":{\"items\":[{\"fieldRef\":{\"fieldPath\":\"metadata.labels\"},\"path\":\"labels\"},{\"fieldRef\":{\"fieldPath\":\"metadata.annotations\"},\"path\":\"annotations\"}]},\"name\":\"podinfo\"}]}}\n"
kubernetes.io/config.seen="2021-01-30T22:50:35.136835626+08:00"
kubernetes.io/config.source="api"
[root@k8s01 stroage]# kubectl exec -n demo downwardapi-volume-demo -it -- /bin/sh
/ # ls
bin dev etc home proc root sys tmp usr var
/ # cd /etc/podinfo
/etc/podinfo # ls
annotations labels
/etc/podinfo # cat labels
cluster="downward-api-test-cluster1"
rack="rack-123"
/etc/podinfo # cat annotations
annotation1="345"
annotation2="456"
cni.projectcalico.org/podIP="10.244.236.130/32"
cni.projectcalico.org/podIPs="10.244.236.130/32"
kubectl.kubernetes.io/last-applied-configuration="{\"apiVersion\":\"v1\",\"kind\":\"Pod\",\"metadata\":{\"annotations\":{\"annotation1\":\"345\",\"annotation2\":\"456\"},\"labels\":{\"cluster\":\"downward-api-test-cluster1\",\"rack\":\"rack-123\",\"zone\":\"us-east-coast\"},\"name\":\"downwardapi-volume-demo\",\"namespace\":\"demo\"},\"spec\":{\"containers\":[{\"args\":[\"while true; do if [[ -e /etc/podinfo/labels ]]; then echo -en '\\\\n\\\\n'; cat /etc/podinfo/labels; fi; if [[ -e /etc/podinfo/annotations ]]; then echo -en '\\\\n\\\\n'; cat /etc/podinfo/annotations; fi; sleep 5; done;\"],\"command\":[\"sh\",\"-c\"],\"image\":\"busybox:1.28\",\"name\":\"volume-test-container\",\"volumeMounts\":[{\"mountPath\":\"/etc/podinfo\",\"name\":\"podinfo\"}]}],\"volumes\":[{\"downwardAPI\":{\"items\":[{\"fieldRef\":{\"fieldPath\":\"metadata.labels\"},\"path\":\"labels\"},{\"fieldRef\":{\"fieldPath\":\"metadata.annotations\"},\"path\":\"annotations\"}]},\"name\":\"podinfo\"}]}}\n"
kubernetes.io/config.seen="2021-01-30T22:50:35.136835626+08:00"
kubernetes.io/config.source="api"
数据变量更新
对于挂载目录，文件
1 | / # ls -alh /etc/podinfo/ |
对于环境变量
目前有个开源工具 Reloader，通过 watch ConfigMap 和 Secret 等，一旦发现对象更新，就自动触发对 Deployment 或 StatefulSet 等工作负载对象进行滚动升级。
可以参考 ConfigMap 的热更新
不可变 Secret 和 ConfigMap
添加字段1
immurable: true