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kubernetes之configmap,深度解析mountPath,subPath,key,path的关系和作用
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参考：https://www.cnblogs.com/breezey/p/6582082.html
我们知道，在几乎所有的应用开发中，都会涉及到配置文件的变更，比如说在web的程序中，需要连接数据库，缓存甚至是队列等等。而我们的一个应用程序从写第一行代码开始，要经历开发环境、测试环境、预发布环境只到最终的线上环境。而每一个环境都要定义其独立的各种配置。如果我们不能很好的管理这些配置文件，你的运维工作将顿时变的无比的繁琐。为此业内的一些大公司专门开发了自己的一套配置管理中心，如360的Qcon，百度的disconf等。kubernetes也提供了自己的一套方案，即ConfigMap。kubernetes通过ConfigMap来实现对容器中应用的配置管理。
1.创建configmap1.1 通过yaml创建
我们先来看第一种，在yaml文件中，配置文件以key-value键值对的形式保存，当然也可以直接放一个完整的配置文件，在下面的示例中，cache_hst、cache_port、cache_prefix即是key-value键值对，而app.properties和my.cnf都是配置文件：
[root@k8s-master k8s-objs]# pwd
/root/k8s-objs
[root@k8s-master k8s-objs]# cat configmap-test1.yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: test-cfg
namespace: default
data:
cache_host: mysql-k8s
cache_port: ""
cache_prefix: k8s
my.cnf: |
[mysqld]
log-bin = mysql-bin
app.properties: |
property. = value-
property. = value-
property. = value-
[root@k8s-master k8s-objs]#
[root@k8s-master k8s-objs]# kubectl create -f configmap-test1.yaml
configmap/test-cfg created[root@k8s-master k8s-objs]# kubectl get configmaps
NAME DATA AGE
test-cfg 85s
[root@k8s-master k8s-objs]# kubectl describe pod test-cfg
Error from server (NotFound): pods "test-cfg" not found
[root@k8s-master k8s-objs]# kubectl describe configmap test-cfg
Name: test-cfg
Namespace: default
Labels: <none>
Annotations: <none>Data
====
app.properties:
----
property. = value-
property. = value-
property. = value-cache_host:
----
mysql-k8s
cache_port:
----cache_prefix:
----
k8s
my.cnf:
----
[mysqld]
log-bin = mysql-binEvents: <none>
[root@k8s-master k8s-objs]#
1.2 通过命令创建configmap
kubectl create configmap test-config3 --from-literal=db.host=10.5.10.116 --from-literal=db.port='3306'
##直接将文件创建为configmap
##kubectl create configmap test-config --from-file=./configs ##将该目录下的所有配置文件创建为configmap
##kubectl create configmap test-config2 --from-file=./configs/db.conf --from-file=./configs/cache.conf
[root@k8s-master k8s-objs]# kubectl create configmap test-config3 --from-literal=db.host=10.5.10.116 --from-literal=db.port=''
configmap/test-config3 created
[root@k8s-master k8s-objs]# kubectl get configmaps
NAME DATA AGE
test-cfg 6m1s
test-config3 9s
[root@k8s-master k8s-objs]# kubectl describe configmap test-cfg3
Error from server (NotFound): configmaps "test-cfg3" not found
[root@k8s-master k8s-objs]# kubectl describe configmap test-config3
Name: test-config3
Namespace: default
Labels: <none>
Annotations: <none>Data
====
db.host:
----
10.5.10.116
db.port:
----Events: <none>
[root@k8s-master k8s-objs]#
查看属性
[root@k8s-master k8s-objs]# kubectl get configmaps -o yaml
apiVersion: v1
items:
- apiVersion: v1
data:
app.properties: |
property. = value-
property. = value-
property. = value-
cache_host: mysql-k8s
cache_port: ""
cache_prefix: k8s
my.cnf: |
[mysqld]
log-bin = mysql-bin
kind: ConfigMap
metadata:
creationTimestamp: "2019-04-11T08:25:13Z"
name: test-cfg
namespace: default
resourceVersion: ""
selfLink: /api/v1/namespaces/default/configmaps/test-cfg
uid: 544cc424-5c33-11e9-a5c3-000c291ae345###第二个configmap
- apiVersion: v1
data:
db.host: 10.5.10.116
db.port: ""
kind: ConfigMap
metadata:
creationTimestamp: "2019-04-11T08:31:05Z"
name: test-config3
namespace: default
resourceVersion: ""
selfLink: /api/v1/namespaces/default/configmaps/test-config3
uid: 261ab5e2-5c34-11e9-a5c3-000c291ae345
kind: List
metadata:
resourceVersion: ""
selfLink: ""
2 使用configmap2.1 作为环境变量[root@k8s-master k8s-objs]# cat pod-configmap-testenv.yaml
apiVersion: v1
kind: Pod
metadata:
labels:
purpose: test-configmap
name: testenv
spec:
containers:
- name: test-configmap
image: tomcat:
imagePullPolicy: IfNotPresent
#command: [ "/bin/sh", "-c", "echo $(MY_CACHE_HOST)" ]
env:
- name: MY_CACHE_HOST
valueFrom:
configMapKeyRef:
name: test-cfg
key: cache_host
[root@k8s-master k8s-objs]#
[root@k8s-master k8s-objs]# kubectl create -f pod-configmap-testenv.yaml
pod/testenv created
root@k8s-master k8s-objs]# kubectl get pod
NAME READY STATUS RESTARTS AGE
hello-5cd4456b66-gstq6 1/1 Running 1 8d
hello-5cd4456b66-sb5px 1/1 Running 1 8d
testenv 1/1 Running 0 7s#查看containerid
[root@k8s-master k8s-objs]# kubectl describe pod testenv
Name: testenv
Namespace: default
Priority: 0
PriorityClassName: <none>
Node: k8s-node1/192.168.111.131
Start Time: Fri, 12 Apr 2019 08:28:27 +0800
Labels: purpose=test-configmap
Annotations: <none>
Status: Running
IP: 10.244.1.69
Containers:
test-configmap:
Container ID: docker://7c76ff1602561c498a537ea0bcd3bb0a244a7ef9ec3cdc34b6ba03577d889a93
Image: tomcat:8
Image ID: docker-pullable://tomcat@sha256:3e3d18321127bb9114f4226f95802d3899aeec4c36df84d0359e5da300e9bc72
Port: <none>
Host Port: <none>
State: Running
Started: Fri, 12 Apr 2019 08:28:33 +0800
Ready: True
Restart Count: 0
Environment:
MY_CACHE_HOST: <set to the key 'cache_host' of config map 'test-cfg'> Optional: false
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-92rjn (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
default-token-92rjn:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-92rjn
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute for 300s
node.kubernetes.io/unreachable:NoExecute for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 2m49s default-scheduler Successfully assigned default/testenv to k8s-node1
Normal Pulled 2m44s kubelet, k8s-node1 Container image "tomcat:8" already present on machine
Normal Created 2m44s kubelet, k8s-node1 Created container test-configmap
Normal Started 2m43s kubelet, k8s-node1 Started container test-configmap
[root@k8s-master k8s-objs]#
[root@k8s-master k8s-objs]# cat pod-configmap-testenv.yaml
apiVersion: v1
kind: Pod
metadata:
labels:
purpose: test-configmap
name: testenv
spec:
containers:
- name: test-configmap
image: tomcat:
imagePullPolicy: IfNotPresent
#command: [ "/bin/sh", "-c", "echo $(MY_CACHE_HOST)" ]
env:
- name: MY_CACHE_HOST
valueFrom:
configMapKeyRef:
name: test-cfg
key: cache_host
[root@k8s-master k8s-objs]#
[root@k8s-master k8s-objs]# kubectl create -f pod-configmap-testenv.yaml
pod/testenv created
root@k8s-master k8s-objs]# kubectl get pod
NAME READY STATUS RESTARTS AGE
hello-5cd4456b66-gstq6 1/1 Running 1 8d
hello-5cd4456b66-sb5px 1/1 Running 1 8d
testenv 1/1 Running 0 7s#查看containerid
[root@k8s-master k8s-objs]# kubectl describe pod testenv
Name: testenv
Namespace: default
Priority: 0
PriorityClassName: <none>
Node: k8s-node1/192.168.111.131
Start Time: Fri, 12 Apr 2019 08:28:27 +0800
Labels: purpose=test-configmap
Annotations: <none>
Status: Running
IP: 10.244.1.69
Containers:
test-configmap:
Container ID: docker://7c76ff1602561c498a537ea0bcd3bb0a244a7ef9ec3cdc34b6ba03577d889a93
Image: tomcat:8
Image ID: docker-pullable://tomcat@sha256:3e3d18321127bb9114f4226f95802d3899aeec4c36df84d0359e5da300e9bc72
Port: <none>
Host Port: <none>
State: Running
Started: Fri, 12 Apr 2019 08:28:33 +0800
Ready: True
Restart Count: 0
Environment:
MY_CACHE_HOST: <set to the key 'cache_host' of config map 'test-cfg'> Optional: false
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-92rjn (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
default-token-92rjn:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-92rjn
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute for 300s
node.kubernetes.io/unreachable:NoExecute for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 2m49s default-scheduler Successfully assigned default/testenv to k8s-node1
Normal Pulled 2m44s kubelet, k8s-node1 Container image "tomcat:8" already present on machine
Normal Created 2m44s kubelet, k8s-node1 Created container test-configmap
Normal Started 2m43s kubelet, k8s-node1 Started container test-configmap
[root@k8s-master k8s-objs]#
进入kubernetes中的pod的容器中,
kubectl exec -it testenv -n default -- /bin/bash #退出exit
[root@k8s-master k8s-objs]# kubectl exec -it testenv -n default -- /bin/bash ##下面标红表示新的pod主机名，即已成功进入pod
root@testenv:/usr/local/tomcat#
root@testenv:/usr/local/tomcat# echo $MY_CACHE_HOST #查看环境变量是否生效
mysql-k8s
root@testenv:/usr/local/tomcat# exit
2.2 挂载文件数据卷2.2.1使用volume将ConfigMap作为文件或目录直接挂载，其中每一个key-value键值对都会生成一个文件，key为文件名，value为内容
查看configmap
[root@k8s-master k8s-objs]# kubectl get configmap
NAME DATA AGE
test-cfg 16h
test-config3 16h
[root@k8s-master k8s-objs]# kubectl get configmap test-cfg -o yaml
apiVersion: v1
data:
app.properties: |
property. = value-
property. = value-
property. = value-
cache_host: mysql-k8s
cache_port: ""
cache_prefix: k8s
my.cnf: |
[mysqld]
log-bin = mysql-bin
kind: ConfigMap
metadata:
creationTimestamp: "2019-04-11T08:25:13Z"
name: test-cfg
namespace: default
resourceVersion: ""
selfLink: /api/v1/namespaces/default/configmaps/test-cfg
uid: 544cc424-5c33-11e9-a5c3-000c291ae345
[root@k8s-master k8s-objs]#
创建pod,并挂载volume
[root@k8s-master k8s-objs]# cat pod-configmap-testvolume.yaml
apiVersion: v1
kind: Pod
metadata:
labels:
purpose: test-configmap-volume
name: testvolume
spec:
containers:
- name: test-configmap-volume
image: tomcat:
imagePullPolicy: IfNotPresent
#command: [ "/bin/sh", "-c", "echo $(MY_CACHE_HOST)" ]
volumeMounts:
- name: config-volume
mountPath: /etc/config
volumes:
- name: config-volume
configMap:
name: test-cfg[root@k8s-master k8s-objs]#
[root@k8s-master k8s-objs]# kubectl create -f pod-configmap-testvolume.yaml
pod/testvolume created
[root@k8s-master k8s-objs]# kubectl get pod
NAME READY STATUS RESTARTS AGE
hello-5cd4456b66-gstq6 / Running 8d
hello-5cd4456b66-sb5px / Running 8d
testvolume / Running 113s
[root@k8s-master k8s-objs]# kubectl describe pod testvolume
Name: testvolume
Namespace: default
Priority:
PriorityClassName: <none>
Node: k8s-node1/192.168.111.131
Start Time: Fri, Apr :: +
Labels: purpose=test-configmap-volume
Annotations: <none>
Status: Running
IP: 10.244.1.70
Containers:
test-configmap-volume:
Container ID: docker://16de1a9dec62564d6e7e50a3167581e9be8151c388707e8f48f4f5152a0ed83a
Image: tomcat:
Image ID: docker-pullable://tomcat@sha256:3e3d18321127bb9114f4226f95802d3899aeec4c36df84d0359e5da300e9bc72
Port: <none>
Host Port: <none>
State: Running
Started: Fri, Apr :: +
Ready: True
Restart Count:
Environment: <none>
Mounts:
/etc/config from config-volume (rw)
/var/run/secrets/kubernetes.io/serviceaccount from default-token-92rjn (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
config-volume:
Type: ConfigMap (a volume populated by a ConfigMap)
Name: test-cfg
Optional: false
default-token-92rjn:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-92rjn
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute for 300s
node.kubernetes.io/unreachable:NoExecute for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 2m45s default-scheduler Successfully assigned default/testvolume to k8s-node1
Normal Pulled 2m42s kubelet, k8s-node1 Container image "tomcat:8" already present on machine
Normal Created 2m42s kubelet, k8s-node1 Created container test-configmap-volume
Normal Started 2m42s kubelet, k8s-node1 Started container test-configmap-volume
[root@k8s-master k8s-objs]#
进入kubernetes的pod,
[root@k8s-master k8s-objs]# kubectl get pod
NAME READY STATUS RESTARTS AGE
hello-5cd4456b66-gstq6 / Running 8d
hello-5cd4456b66-sb5px / Running 8d
testvolume / Running 3m56s
[root@k8s-master k8s-objs]# kubectl exec -it testsvolume /bin/bash
Error from server (NotFound): pods "testsvolume" not found
[root@k8s-master k8s-objs]# kubectl exec -it testvolume /bin/bash
root@testvolume:/usr/local/tomcat# cd /etc/config
root@testvolume:/etc/config# ls
app.properties cache_host cache_port cache_prefix my.cnf
root@testvolume:/etc/config# ll
bash: ll: command not found
root@testvolume:/etc/config# ls -l ##对照发现，使用volume将ConfigMap作为文件或目录直接挂载，其中每一个key-value键值对都会生成一个文件，key为文件名，value为内容
total
lrwxrwxrwx root root Apr : app.properties -> ..data/app.properties
lrwxrwxrwx root root Apr : cache_host -> ..data/cache_host
lrwxrwxrwx root root Apr : cache_port -> ..data/cache_port
lrwxrwxrwx root root Apr : cache_prefix -> ..data/cache_prefix
lrwxrwxrwx root root Apr : my.cnf -> ..data/my.cnf
root@testvolume:/etc/config# cat app.properties
property. = value-
property. = value-
property. = value-
root@testvolume:/etc/config# cat cache_host
mysql-k8sroot@testvolume:/etc/config# cat cache_port
root@testvolume:/etc/config# cat cache_prefix
k8sroot@testvolume:/etc/config# cat my.cnf
[mysqld]
log-bin = mysql-bin
root@testvolume:/usr/local/tomcat# echo $cache_host ##并没有自动生成环境变量root@testvolume:/usr/local/tomcat#
root@testvolume:/etc/config# exit
2.2.2 另一种方式，只挂载某个key,并支持相对路径，其中一个key生成的文件路径名和文件名相同
[root@k8s-master k8s-objs]# cat pod-configmap-testvolume.yaml
apiVersion: v1
kind: Pod
metadata:
labels:
purpose: test-configmap-volume
name: testvolume
spec:
containers:
- name: test-configmap-volume
image: tomcat:
imagePullPolicy: IfNotPresent
#command: [ "/bin/sh", "-c", "echo $(MY_CACHE_HOST)" ]
volumeMounts:
- name: config-volume
mountPath: /etc/config
volumes:
- name: config-volume
configMap:
name: test-cfg
items:
- key: cache_host
path: path/to/special-key-cache #path中的最后一级“special-key-cache”为文件名
- key: app.properties
path: app.properties
[root@k8s-master k8s-objs]# kubectl create -f pod-configmap-testvolume.yaml
pod/testvolume created
[root@k8s-master k8s-objs]# kubectl get pod
NAME READY STATUS RESTARTS AGE
hello-5cd4456b66-gstq6 / Running 8d
hello-5cd4456b66-sb5px / Running 8d
testvolume / Running 12s
[root@k8s-master k8s-objs]# kubectl describe pod testvolume
Name: testvolume
Namespace: default
Priority:
PriorityClassName: <none>
Node: k8s-node1/192.168.111.131
Start Time: Fri, Apr :: +
Labels: purpose=test-configmap-volume
Annotations: <none>
Status: Running
IP: 10.244.1.71
Containers:
test-configmap-volume:
Container ID: docker://227d2ab39823087193f1830309c73af5408c85f634eb5c7fce9c668533766b76
Image: tomcat:
Image ID: docker-pullable://tomcat@sha256:3e3d18321127bb9114f4226f95802d3899aeec4c36df84d0359e5da300e9bc72
Port: <none>
Host Port: <none>
State: Running
Started: Fri, Apr :: +
Ready: True
Restart Count:
Environment: <none>
Mounts:
/etc/config from config-volume (rw)
/var/run/secrets/kubernetes.io/serviceaccount from default-token-92rjn (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
config-volume:
Type: ConfigMap (a volume populated by a ConfigMap)
Name: test-cfg
Optional: false
default-token-92rjn:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-92rjn
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute for 300s
node.kubernetes.io/unreachable:NoExecute for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 2m27s default-scheduler Successfully assigned default/testvolume to k8s-node1
Normal Pulled 2m24s kubelet, k8s-node1 Container image "tomcat:8" already present on machine
Normal Created 2m23s kubelet, k8s-node1 Created container test-configmap-volume
Normal Started 2m23s kubelet, k8s-node1 Started container test-configmap-volume
[root@k8s-master k8s-objs]#
进入pod
[root@k8s-master k8s-objs]# kubectl get pod
NAME READY STATUS RESTARTS AGE
hello-5cd4456b66-gstq6 / Running 8d
hello-5cd4456b66-sb5px / Running 8d
testvolume / Running 3m24s
[root@k8s-master k8s-objs]# kubectl exec -it testvolume /bin/bash
root@testvolume:/usr/local/tomcat# cd /etc/config
root@testvolume:/etc/config# ls -l #在目录/etc/config下生成一个文件（/etc/config/app.properties）和一个带path目录的文件(/etc/config/path/to/special-key-cache)
total
lrwxrwxrwx root root Apr : app.properties -> ..data/app.properties
lrwxrwxrwx root root Apr : path -> ..data/path
root@testvolume:/etc/config# ls app.properties
app.properties
root@testvolume:/etc/config# cat app.properties/app.properties
cat: app.properties/app.properties: Not a directory
root@testvolume:/etc/config# cd app.properties
bash: cd: app.properties: Not a directory
root@testvolume:/etc/config# cat app.properties ##说明key:app.properties的path项用文件名相当于没有起任何作用
property. = value-
property. = value-
property. = value-
root@testvolume:/etc/config# pwd
/etc/config
root@testvolume:/etc/config# cd path/to/special-key-cache
bash: cd: path/to/special-key-cache: Not a directory
root@testvolume:/etc/config# cd path
root@testvolume:/etc/config/path# cd to
root@testvolume:/etc/config/path/to# cd special-key-cache
bash: cd: special-key-cache: Not a directory
root@testvolume:/etc/config/path/to# pwd
/etc/config/path/to
root@testvolume:/etc/config/path/to# ls
special-key-cache
root@testvolume:/etc/config/path/to# cat special-key-cache
mysql-k8sroot@testvolume:/etc/config/path/to# exit
configmap在pod容器中成功生成了文件
3 深度解析mountPath,subPath,key,path的关系和作用
结论：
kubernetes key (pod.spec.volums[0].configMap.items[0].key)用于指定configMap中的哪些条目可用于挂载,如2.2.2
kubernetes path (pod.spec.volums[0].configMap.items[0].path)用于将key重命名，如案例3.3
kubernetes suPath (pod.spec.containers[0].volumeMounts.subPath)决定容器中有无挂载（按名字从key，有path时以path为主，中比对是否存在要的条目）。
kubernetes mountPath (pod.spec.containers[0].volumeMounts.mountPath)决定容器中挂载的结果文件名。没有subPath项时如案例2.2.1，此项仅指定路径。有subPath时且subPath筛选结果为true时如案例3.1，此项指定路径和文件名，此时文件名可随意指定如案例3.4和3.5；有subPath但subPath筛选结果为false时如案例3.2，此项指定路径（最后一级目录名为文件名）
3.1 mountPath结合subPath作用
有subPath时且subPath推荐筛选结果为true，mountPath指定到文件名
注：subPath只是将volume.items.key中多个key进行筛选，只挂载需要的文件，相当于2.2.2中app.properties保留，其它key不挂载
[root@k8s-master k8s-objs]# cat pod-configmap-testvolume.yaml
apiVersion: v1
kind: Pod
metadata:
labels:
purpose: test-configmap-volume
name: testvolume
spec:
containers:
- name: test-configmap-volume
image: tomcat:
imagePullPolicy: IfNotPresent
#command: [ "/bin/sh", "-c", "echo $(MY_CACHE_HOST)" ]
volumeMounts:
- name: config-volume
mountPath: /etc/config/app.properties #此处配合suPath使用时，app.properties为文件名，即pod容器中只生成了/etc/config目录，目录之下 为文件，只有一个名为app.properties的文件（subPath筛选只挂载app.properties文件）
subPath: app.properties
volumes:
- name: config-volume
configMap:
name: test-cfg
items:
- key: cache_host
path: path/to/special-key-cache
- key: app.properties
path: app.properties
[root@k8s-master k8s-objs]# kubectl create -f pod-configmap-testvolume.yaml
pod/testvolume created
[root@k8s-master k8s-objs]# kubectl get pod
NAME READY STATUS RESTARTS AGE
hello-5cd4456b66-gstq6 / Running 8d
hello-5cd4456b66-sb5px / Running 8d
testvolume / Running 17s
[root@k8s-master k8s-objs]#
[root@k8s-master k8s-objs]# kubectl describe pod testvolume
Name: testvolume
Namespace: default
Priority:
PriorityClassName: <none>
Node: k8s-node1/192.168.111.131
Start Time: Fri, Apr :: +
Labels: purpose=test-configmap-volume
Annotations: <none>
Status: Running
IP: 10.244.1.72
Containers:
test-configmap-volume:
Container ID: docker://ef581eaaf8bd895bce8d4e77f66b8c704b557dee186bf72e00e1aa3dbb7390f4
Image: tomcat:
Image ID: docker-pullable://tomcat@sha256:3e3d18321127bb9114f4226f95802d3899aeec4c36df84d0359e5da300e9bc72
Port: <none>
Host Port: <none>
State: Running
Started: Fri, Apr :: +
Ready: True
Restart Count:
Environment: <none>
Mounts:
/etc/config/app.properties from config-volume (rw,path="app.properties")
/var/run/secrets/kubernetes.io/serviceaccount from default-token-92rjn (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
config-volume:
Type: ConfigMap (a volume populated by a ConfigMap)
Name: test-cfg
Optional: false
default-token-92rjn:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-92rjn
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute for 300s
node.kubernetes.io/unreachable:NoExecute for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 2m13s default-scheduler Successfully assigned default/testvolume to k8s-node1
Normal Pulled 2m10s kubelet, k8s-node1 Container image "tomcat:8" already present on machine
Normal Created 2m10s kubelet, k8s-node1 Created container test-configmap-volume
Normal Started 2m10s kubelet, k8s-node1 Started container test-configmap-volume
[root@k8s-master k8s-objs]#
进入pod
[root@k8s-master k8s-objs]# kubectl exec -it testvolume /bin/bash
root@testvolume:/usr/local/tomcat# cd /etc/config
root@testvolume:/etc/config# ls
app.properties
root@testvolume:/etc/config# ll
bash: ll: command not found
root@testvolume:/etc/config# ls
app.properties
root@testvolume:/etc/config# ls -l
total
-rw-r--r-- root root Apr : app.properties
root@testvolume:/etc/config# cd app.properties
bash: cd: app.properties: Not a directory
root@testvolume:/etc/config# cat app.properties
property.1 = value-1
property.2 = value-2
property.3 = value-3
root@testvolume:/etc/config#
3.2有subPath但筛选结果为false,
容器中生成一个空目录/etc/config/app.properties，无文件
解析。subPath筛选范围优先级为pod.spec.volums[0].configMap.items[0].path>pod.spec.volums[0].configMap.items[0].key>configMap.key，本例中为path,即在path指定的条目【“cache_host”,"app-properties "注意中间是横杠不是点】找是否有subPath项“app.properties”注意中间为点，查找结果为false,所以无文件挂载。容器将“/etc/config/app.properties”当成一个待创建的路径。
[root@k8s-master k8s-objs]# vi pod-configmap-testvolume.yamlapiVersion: v1
kind: Pod
metadata:
labels:
purpose: test-configmap-volume
name: testvolume
spec:
containers:
- name: test-configmap-volume
image: tomcat:
imagePullPolicy: IfNotPresent
#command: [ "/bin/sh", "-c", "echo $(MY_CACHE_HOST)" ]
volumeMounts:
- name: config-volume
mountPath: /etc/config/app.properties #此时此处app.properties为文件名
subPath: app.properties
volumes:
- name: config-volume
configMap:
name: test-cfg
items:
- key: cache_host
path: path/to/special-key-cache
- key: app.properties
path: app-properties #此处path相当于更改文件名mv app.properties app-properties
[root@k8s-master k8s-objs]# kubectl exec -it testvolume /bin/bash
root@testvolume:/usr/local/tomcat# cd /etc/config
root@testvolume:/etc/config# ls
app.properties
root@testvolume:/etc/config# ll #此目录下只有一个子目录
bash: ll: command not found
root@testvolume:/etc/config# ls -l
total
drwxrwxrwx root root Apr : app.properties
root@testvolume:/etc/config# cat app.properties
cat: app.properties: Is a directory
root@testvolume:/etc/config# cd app.properties
root@testvolume:/etc/config/app.properties# ls
root@testvolume:/etc/config/app.properties# ls #此目录下为空
root@testvolume:/etc/config/app.properties#
3.3无 subPath,path相当于重命名[root@k8s-master k8s-objs]# cat pod-configmap-testvolume.yaml
apiVersion: v1
kind: Pod
metadata:
labels:
purpose: test-configmap-volume
name: testvolume
spec:
containers:
- name: test-configmap-volume
image: tomcat:
imagePullPolicy: IfNotPresent
#command: [ "/bin/sh", "-c", "echo $(MY_CACHE_HOST)" ]
volumeMounts:
- name: config-volume
mountPath: /etc/config/app.properties ##此处app.properties为目录
# subPath: app.properties
volumes:
- name: config-volume
configMap:
name: test-cfg
items:
- key: cache_host
path: path/to/special-key-cache
- key: app.properties
path: app-properties #此处path相当于更改文件名mv app.properties app-properties
[root@k8s-master k8s-objs]#
[root@k8s-master k8s-objs]# kubectl exec -it testvolume /bin/bash
root@testvolume:/usr/local/tomcat# ls
BUILDING.txt CONTRIBUTING.md LICENSE NOTICE README.md RELEASE-NOTES RUNNING.txt bin conf include lib logs native-jni-lib temp webapps work
root@testvolume:/usr/local/tomcat# cd /etc/config
root@testvolume:/etc/config# ls
app.properties
root@testvolume:/etc/config# ls -l
total
drwxrwxrwx root root Apr : app.properties
root@testvolume:/etc/config# cd app.properties
root@testvolume:/etc/config/app.properties# ls
app-properties path
root@testvolume:/etc/config/app.properties# ls -l
total
lrwxrwxrwx root root Apr : app-properties -> ..data/app-properties
lrwxrwxrwx root root Apr : path -> ..data/path
root@testvolume:/etc/config/app.properties# cat app-properties
property. = value-
property. = value-
property. = value-
root@testvolume:/etc/config/app.properties# cat path
cat: path: Is a directory
root@testvolume:/etc/config/app.properties# cd path
root@testvolume:/etc/config/app.properties/path# ls
to
root@testvolume:/etc/config/app.properties/path# cd to
root@testvolume:/etc/config/app.properties/path/to# ls -l
total
-rw-r--r-- root root Apr : special-key-cache
root@testvolume:/etc/config/app.properties/path/to# cat special-key-cache
mysql-k8sroot@testvolume:/etc/config/app.properties/path/to#
3.4有subPath且筛选结果为true,mouthPath指定文件名，可以和subPath不一样[root@k8s-master k8s-objs]# vi pod-configmap-testvolume.yamlapiVersion: v1
kind: Pod
metadata:
labels:
purpose: test-configmap-volume
name: testvolume
spec:
containers:
- name: test-configmap-volume
image: tomcat:
imagePullPolicy: IfNotPresent
#command: [ "/bin/sh", "-c", "echo $(MY_CACHE_HOST)" ]
volumeMounts:
- name: config-volume
mountPath: /etc/config/app.properties #此处app.properties为文件名
subPath: app-properties #改为与mountPath不一样的文件名时，subPath相当于通过volume筛选configMap中的key(此处为因volumes.configMap.items.path对key进行了重命名)中的条目，即存在subPath时，subPath决定有无，mountPath决定文件名
volumes:
- name: config-volume
configMap:
name: test-cfg
items:
- key: cache_host
path: path/to/special-key-cache
- key: app.properties
path: app-properties[root@k8s-master k8s-objs]# kubectl exec -it testvolume /bin/bash
root@testvolume:/usr/local/tomcat# cd /etc/config
root@testvolume:/etc/config# ls
app.properties
root@testvolume:/etc/config# ls -l
total
-rw-r--r-- root root Apr : app.properties
root@testvolume:/etc/config# cat app.properties
property. = value-
property. = value-
property. = value-
root@testvolume:/etc/config# pwd
/etc/config
root@testvolume:/etc/config# ls
app.properties
root@testvolume:/etc/config# exit
3.5有subPath且筛选结果为true,mouthPath指定文件名，可以和subPath不一样，甚至随意指定为z.txt[root@k8s-master k8s-objs]# vi pod-configmap-testvolume.yamlapiVersion: v1
kind: Pod
metadata:
labels:
purpose: test-configmap-volume
name: testvolume
spec:
containers:
- name: test-configmap-volume
image: tomcat:
imagePullPolicy: IfNotPresent
#command: [ "/bin/sh", "-c", "echo $(MY_CACHE_HOST)" ]
volumeMounts:
- name: config-volume
mountPath: /etc/config/z.txt #subPath决定有无，mountPath决定文件名为z.txt
subPath: app-properties
volumes:
- name: config-volume
configMap:
name: test-cfg
items:
- key: cache_host
path: path/to/special-key-cache
- key: app.properties
path: app-properties[root@k8s-master k8s-objs]# kubectl exec -it testvolume /bin/bash
root@testvolume:/usr/local/tomcat# cd /etc/config
root@testvolume:/etc/config# ls
z.txt
root@testvolume:/etc/config# pwd
/etc/config
root@testvolume:/etc/config# cat z.txt
property. = value-
property. = value-
property. = value-
root@testvolume:/etc/config#
[root@k8s-master k8s-objs]# cat pod-configmap-testvolume.yaml
apiVersion: v1
kind: Pod
metadata:
labels:
purpose: test-configmap-volume
name: testvolume
spec:
containers:
- name: test-configmap-volume
image: tomcat:
imagePullPolicy: IfNotPresent
#command: [ "/bin/sh", "-c", "echo $(MY_CACHE_HOST)" ]
volumeMounts:
- name: config-volume
mountPath: /etc/config/app.properties ##此处app.properties为目录
# subPath: app.properties
volumes:
- name: config-volume
configMap:
name: test-cfg
items:
- key: cache_host
path: path/to/special-key-cache
- key: app.properties
path: app-properties #此处path相当于更改文件名mv app.properties app-properties
[root@k8s-master k8s-objs]#
[root@k8s-master k8s-objs]# kubectl exec -it testvolume /bin/bash
root@testvolume:/usr/local/tomcat# ls
BUILDING.txt CONTRIBUTING.md LICENSE NOTICE README.md RELEASE-NOTES RUNNING.txt bin conf include lib logs native-jni-lib temp webapps work
root@testvolume:/usr/local/tomcat# cd /etc/config
root@testvolume:/etc/config# ls
app.properties
root@testvolume:/etc/config# ls -l
total
drwxrwxrwx root root Apr : app.properties
root@testvolume:/etc/config# cd app.properties
root@testvolume:/etc/config/app.properties# ls
app-properties path
root@testvolume:/etc/config/app.properties# ls -l
total
lrwxrwxrwx root root Apr : app-properties -> ..data/app-properties
lrwxrwxrwx root root Apr : path -> ..data/path
root@testvolume:/etc/config/app.properties# cat app-properties
property. = value-
property. = value-
property. = value-
root@testvolume:/etc/config/app.properties# cat path
cat: path: Is a directory
root@testvolume:/etc/config/app.properties# cd path
root@testvolume:/etc/config/app.properties/path# ls
to
root@testvolume:/etc/config/app.properties/path# cd to
root@testvolume:/etc/config/app.properties/path/to# ls -l
total
-rw-r--r-- root root Apr : special-key-cache
root@testvolume:/etc/config/app.properties/path/to# cat special-key-cache
mysql-k8sroot@testvolume:/etc/config/app.properties/path/to#
[root@k8s-master k8s-objs]# vi pod-configmap-testvolume.yamlapiVersion: v1
kind: Pod
metadata:
labels:
purpose: test-configmap-volume
name: testvolume
spec:
containers:
- name: test-configmap-volume
image: tomcat:
imagePullPolicy: IfNotPresent
#command: [ "/bin/sh", "-c", "echo $(MY_CACHE_HOST)" ]
volumeMounts:
- name: config-volume
mountPath: /etc/config/app.properties #此处app.properties为文件名
subPath: app-properties #改为与mountPath不一样的文件名时，subPath相当于通过volume筛选configMap中的key(此处为因volumes.configMap.items.path对key进行了重命名)中的条目，即存在subPath时，subPath决定有无，mountPath决定文件名
volumes:
- name: config-volume
configMap:
name: test-cfg
items:
- key: cache_host
path: path/to/special-key-cache
- key: app.properties
path: app-properties[root@k8s-master k8s-objs]# kubectl exec -it testvolume /bin/bash
root@testvolume:/usr/local/tomcat# cd /etc/config
root@testvolume:/etc/config# ls
app.properties
root@testvolume:/etc/config# ls -l
total
-rw-r--r-- root root Apr : app.properties
root@testvolume:/etc/config# cat app.properties
property. = value-
property. = value-
property. = value-
root@testvolume:/etc/config# pwd
/etc/config
root@testvolume:/etc/config# ls
app.properties
root@testvolume:/etc/config# exit
3.5有subPath且筛选结果为true,mouthPath指定文件名，可以和subPath不一样，甚至随意指定为z.txt[root@k8s-master k8s-objs]# vi pod-configmap-testvolume.yamlapiVersion: v1
kind: Pod
metadata:
labels:
purpose: test-configmap-volume
name: testvolume
spec:
containers:
- name: test-configmap-volume
image: tomcat:
imagePullPolicy: IfNotPresent
#command: [ "/bin/sh", "-c", "echo $(MY_CACHE_HOST)" ]
volumeMounts:
- name: config-volume
mountPath: /etc/config/z.txt #subPath决定有无，mountPath决定文件名为z.txt
subPath: app-properties
volumes:
- name: config-volume
configMap:
name: test-cfg
items:
- key: cache_host
path: path/to/special-key-cache
- key: app.properties
path: app-properties[root@k8s-master k8s-objs]# kubectl exec -it testvolume /bin/bash
root@testvolume:/usr/local/tomcat# cd /etc/config
root@testvolume:/etc/config# ls
z.txt
root@testvolume:/etc/config# pwd
/etc/config
root@testvolume:/etc/config# cat z.txt
property. = value-
property. = value-
property. = value-
root@testvolume:/etc/config#
[root@k8s-master k8s-objs]# vi pod-configmap-testvolume.yamlapiVersion: v1
kind: Pod
metadata:
labels:
purpose: test-configmap-volume
name: testvolume
spec:
containers:
- name: test-configmap-volume
image: tomcat:
imagePullPolicy: IfNotPresent
#command: [ "/bin/sh", "-c", "echo $(MY_CACHE_HOST)" ]
volumeMounts:
- name: config-volume
mountPath: /etc/config/z.txt #subPath决定有无，mountPath决定文件名为z.txt
subPath: app-properties
volumes:
- name: config-volume
configMap:
name: test-cfg
items:
- key: cache_host
path: path/to/special-key-cache
- key: app.properties
path: app-properties[root@k8s-master k8s-objs]# kubectl exec -it testvolume /bin/bash
root@testvolume:/usr/local/tomcat# cd /etc/config
root@testvolume:/etc/config# ls
z.txt
root@testvolume:/etc/config# pwd
/etc/config
root@testvolume:/etc/config# cat z.txt
property. = value-
property. = value-
property. = value-
root@testvolume:/etc/config#
