根据实践学习K8S---4.使用ConfigMap对象来统一下发配置1

1.在生成环境中,相同集群的应用配置是一样的,如果要修改其中一个配置,就需要修改所有节点的配置,.
K8S中通过ConfigMap可以统一下发变量和配置文件.

以tomcat为例,先在pod中安装tomcat:

[root@centos-7c556897c8-pxj9b /]# yum install tomcat

安装完成之后配置文件在:

[root@centos-7c556897c8-pxj9b tomcat]# pwd
/etc/tomcat
[root@centos-7c556897c8-pxj9b tomcat]# ll
total 216
drwxrwxr-x 3 root tomcat     23 Jan 27 09:15 Catalina
-rw-r--r-- 1 root tomcat  13443 Aug  7  2017 catalina.policy
-rw-r--r-- 1 root tomcat   6496 Aug  7  2017 catalina.properties
drwxr-xr-x 2 root tomcat     20 Jan 27 09:15 conf.d
-rw-r--r-- 1 root tomcat   1394 Aug  7  2017 context.xml
-rw-r--r-- 1 root tomcat    547 Aug  7  2017 log4j.properties
-rw-r--r-- 1 root tomcat   3288 Aug  7  2017 logging.properties
-rw-r--r-- 1 root tomcat   6613 Aug  7  2017 server.xml
-rw-r----- 1 root tomcat   2418 Aug  7  2017 tomcat-users.xml
-rw-r--r-- 1 root tomcat   1651 Aug  7  2017 tomcat.conf
-rw-r--r-- 1 root tomcat 167655 Aug  7  2017 web.xml

下面我们对log4j.properties和server.xml进行统一配置.

先将pod保存成镜像.
1.找到pod所在的节点:

[root@node-1 ~]# kubectl get pod -o wide
NAME                      READY   STATUS    RESTARTS   AGE     IP             NODE     NOMINATED NODE   READINESS GATES
centos-7c556897c8-pxj9b   1/1     Running   0          4d23h   192.168.1.43   node-2   <none>           <none>

2.进入节点进行镜像保存

[root@node-2 ~]# docker ps
CONTAINER ID        IMAGE                                               COMMAND                  CREATED             STATUS              PORTS               NAMES
cfe0858884de        22872cc86f9c                                        "/bin/bash -c -- 'wh鈥   5 days ago          Up 5 days                               k8s_centos_centos-7c556897c8-pxj9b_default_1db8f14a-3900-4826-beab-10b1f170c240_0
a7eaf04cdd29        registry.aliyuncs.com/google_containers/pause:3.1   "/pause"                 5 days ago          Up 5 days                               k8s_POD_centos-7c556897c8-pxj9b_default_1db8f14a-3900-4826-beab-10b1f170c240_0
1f21ee9bada9        ff281650a721                                        "/opt/bin/flanneld -鈥   5 days ago          Up 5 days                               k8s_kube-flannel_kube-flannel-ds-amd64-ngv5r_kube-system_0af8bd3f-2ede-4d7e-973f-babfb621d32d_7
896928f1e17d        c21b0c7400f9                                        "/usr/local/bin/kube鈥   5 days ago          Up 5 days                               k8s_kube-proxy_kube-proxy-mt2xz_kube-system_7298b76b-ecfb-459f-adc0-8d8e0647d0ec_6
0ecb8fdd8d05        registry.aliyuncs.com/google_containers/pause:3.1   "/pause"                 5 days ago          Up 5 days                               k8s_POD_kube-flannel-ds-amd64-ngv5r_kube-system_0af8bd3f-2ede-4d7e-973f-babfb621d32d_7
665a883cbf77        registry.aliyuncs.com/google_containers/pause:3.1   "/pause"                 5 days ago          Up 5 days                               k8s_POD_kube-proxy-mt2xz_kube-system_7298b76b-ecfb-459f-adc0-8d8e0647d0ec_7
[root@node-2 ~]# docker commit --author "dingyz" --
--author       --change       --help         --message      --pause=false  
[root@node-2 ~]# docker commit --author "dingyz" --message "centos7.4-tomcat" cfe0858884de centos:7.4-tomcat
sha256:4a8deb9c9d407ae7f8589a14d468a8f856e098ba80f1487d49b5daa645cb5280
[root@node-2 ~]# docker images
REPOSITORY                                            TAG                        IMAGE ID            CREATED             SIZE
centos                                                7.4-tomcat                 4a8deb9c9d40        11 seconds ago      434MB
centos                                                centos7.4.1708.net-tools   22872cc86f9c        5 days ago          236MB
registry.cn-hangzhou.aliyuncs.com/dingyz/centos       7.4.net-tools              22872cc86f9c        5 days ago          236MB
centos                                                latest                     470671670cac        9 days ago          237MB
nginx                                                 latest                     c7460dfcab50        2 weeks ago         126MB
mysql                                                 5.7                        db39680b63ac        4 weeks ago         437MB
mysql                                                 latest                     ed1ffcb5eff3        4 weeks ago         456MB
registry.aliyuncs.com/google_containers/kube-proxy    v1.16.0                    c21b0c7400f9        4 months ago        86.1MB
registry.aliyuncs.com/google_containers/coredns       1.6.2                      bf261d157914        5 months ago        44.1MB
centos                                                centos7.4.1708             9f266d35e02c        10 months ago       197MB
registry.cn-hangzhou.aliyuncs.com/dingyz/centos       7.4.base                   9f266d35e02c        10 months ago       197MB
registry.cn-hangzhou.aliyuncs.com/userdefine/centos   7.4.base                   9f266d35e02c        10 months ago       197MB
quay-mirror.qiniu.com/coreos/flannel                  v0.11.0-amd64              ff281650a721        12 months ago       52.6MB
registry.aliyuncs.com/google_containers/pause         3.1                        da86e6ba6ca1        2 years ago         742kB
kubeguide/tomcat-app                                  v1                         a29e200a18e9        3 years ago         358MB
nginx                                                 1.7.9                      84581e99d807        5 years ago         91.7MB
[root@node-2 ~]#

可以将镜像导出到其他节点,获取上传到云仓库,让其他节点也可以进行部署.

[root@node-2 ~]# docker save  -o ./centos7.4-tomcat.tar centos:7.4-tomcat 
[root@node-2 ~]# 
[root@node-2 ~]# ls
anaconda-ks.cfg  centos7.4-tomcat.tar  Desktop  Documents  Downloads  initial-setup-ks.cfg  logstash-7.4.2.tar.gz  metricbeat-7.4.2-linux-x86_64.tar.gz  Music  Pictures  Public  Templates  Videos
[root@node-2 ~]# scp centos7.4-tomcat.tar [email protected]:/root

[root@node-3 ~]# ls
anaconda-ks.cfg  centos7.4-tomcat.tar  Desktop  Dockerfile  Documents  Downloads  initial-setup-ks.cfg  Music  Pictures  Public  Templates  test.tar  Videos
[root@node-3 ~]# docker load < centos7.4-tomcat.tar 
c0b8b77dce7c: Loading layer [==================================================>]    200MB/200MB
Loaded image: centos:7.4-tomcat
[root@node-3 ~]# 

返回管理节点,创建配置目录,并添加配置文件:

[root@node-1 tomcat]# pwd
/opt/k8s/configmap/tomcat
[root@node-1 tomcat]# ls
log4j.properties  server.xml
[root@node-1 tomcat]#

创建ConfigMap对象:直接从目录读取所有配置文件内容.

[root@node-1 configmap]# kubectl create configmap tomcat-config --from-file=tomcat
configmap/tomcat-config created
[root@node-1 configmap]# 
[root@node-1 configmap]# 
[root@node-1 configmap]# 
[root@node-1 configmap]# 
[root@node-1 configmap]# kubectl describe configmaps tomcat-config tomcat
Name:         tomcat-config
Namespace:    default
Labels:       <none>
Annotations:  <none>

Data
====
log4j.properties:
----
log4j.rootLogger=debug, R 
log4j.appender.R=org.apache.log4j.RollingFileAppender 
log4j.appender.R.File=${catalina.home}/logs/tomcat.log 
log4j.appender.R.MaxFileSize=10MB 
log4j.appender.R.MaxBackupIndex=10 
log4j.appender.R.layout=org.apache.log4j.PatternLayout 
log4j.appender.R.layout.ConversionPattern=%p %t %c - %m%n 
log4j.logger.org.apache.catalina=DEBUG, R
log4j.logger.org.apache.catalina.core.ContainerBase.[Catalina].[localhost]=DEBUG, R
log4j.logger.org.apache.catalina.core=DEBUG, R
log4j.logger.org.apache.catalina.session=DEBUG, R

server.xml:
----
<?xml version='1.0' encoding='utf-8'?>
<!--
  Licensed to the Apache Software Foundation (ASF) under one or more
  contributor license agreements.  See the NOTICE file distributed with
  this work for additional information regarding copyright ownership.
  The ASF licenses this file to You under the Apache License, Version 2.0
  (the "License"); you may not use this file except in compliance with
  the License.  You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
-->
<!-- Note:  A "Server" is not itself a "Container", so you may not
     define subcomponents such as "Valves" at this level.
     Documentation at /docs/config/server.html
 -->
<Server port="8005" shutdown="SHUTDOWN">
  <Listener className="org.apache.catalina.startup.VersionLoggerListener" />
  <!-- Security listener. Documentation at /docs/config/listeners.html
  <Listener className="org.apache.catalina.security.SecurityListener" />
  -->
  <!--APR library loader. Documentation at /docs/apr.html -->
  <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" />
  <!--Initialize Jasper prior to webapps are loaded. Documentation at /docs/jasper-howto.html -->
  <Listener className="org.apache.catalina.core.JasperListener" />
  <!-- Prevent memory leaks due to use of particular java/javax APIs-->
  <Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />
  <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />
  <Listener className="org.apache.catalina.core.ThreadLocalLeakPreventionListener" />

  <!-- Global JNDI resources
       Documentation at /docs/jndi-resources-howto.html
  -->
  <GlobalNamingResources>
    <!-- Editable user database that can also be used by
         UserDatabaseRealm to authenticate users
    -->
    <Resource name="UserDatabase" auth="Container"
              type="org.apache.catalina.UserDatabase"
              description="User database that can be updated and saved"
              factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
              pathname="conf/tomcat-users.xml" />
  </GlobalNamingResources>

  <!-- A "Service" is a collection of one or more "Connectors" that share
       a single "Container" Note:  A "Service" is not itself a "Container",
       so you may not define subcomponents such as "Valves" at this level.
       Documentation at /docs/config/service.html
   -->
  <Service name="Catalina">

    <!--The connectors can use a shared executor, you can define one or more named thread pools-->
    <!--
    <Executor name="tomcatThreadPool" namePrefix="catalina-exec-"
        maxThreads="150" minSpareThreads="4"/>
    -->


    <!-- A "Connector" represents an endpoint by which requests are received
         and responses are returned. Documentation at :
         Java HTTP Connector: /docs/config/http.html (blocking & non-blocking)
         Java AJP  Connector: /docs/config/ajp.html
         APR (HTTP/AJP) Connector: /docs/apr.html
         Define a non-SSL HTTP/1.1 Connector on port 8080
    -->
    <Connector port="8080" protocol="HTTP/1.1"
               connectionTimeout="20000"
               redirectPort="8443" />
    <!-- A "Connector" using the shared thread pool-->
    <!--
    <Connector executor="tomcatThreadPool"
               port="8080" protocol="HTTP/1.1"
               connectionTimeout="20000"
               redirectPort="8443" />
    -->
    <!-- Define a SSL HTTP/1.1 Connector on port 8443
         This connector uses the BIO implementation that requires the JSSE
         style configuration. When using the APR/native implementation, the
         OpenSSL style configuration is required as described in the APR/native
         documentation -->
    <!--
    <Connector port="8443" protocol="org.apache.coyote.http11.Http11Protocol"
               maxThreads="150" SSLEnabled="true" scheme="https" secure="true"
               clientAuth="false" sslProtocol="TLS" />
    -->

    <!-- Define an AJP 1.3 Connector on port 8009 -->
    <Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />


    <!-- An Engine represents the entry point (within Catalina) that processes
         every request.  The Engine implementation for Tomcat stand alone
         analyzes the HTTP headers included with the request, and passes them
         on to the appropriate Host (virtual host).
         Documentation at /docs/config/engine.html -->

    <!-- You should set jvmRoute to support load-balancing via AJP ie :
    <Engine name="Catalina" defaultHost="localhost" jvmRoute="jvm1">
    -->
    <Engine name="Catalina" defaultHost="localhost">

      <!--For clustering, please take a look at documentation at:
          /docs/cluster-howto.html  (simple how to)
          /docs/config/cluster.html (reference documentation) -->
      <!--
      <Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"/>
      -->

      <!-- Use the LockOutRealm to prevent attempts to guess user passwords
           via a brute-force attack -->
      <Realm className="org.apache.catalina.realm.LockOutRealm">
        <!-- This Realm uses the UserDatabase configured in the global JNDI
             resources under the key "UserDatabase".  Any edits
             that are performed against this UserDatabase are immediately
             available for use by the Realm.  -->
        <Realm className="org.apache.catalina.realm.UserDatabaseRealm"
               resourceName="UserDatabase"/>
      </Realm>

      <Host name="localhost"  appBase="webapps"
            unpackWARs="true" autoDeploy="true">

        <!-- SingleSignOn valve, share authentication between web applications
             Documentation at: /docs/config/valve.html -->
        <!--
        <Valve className="org.apache.catalina.authenticator.SingleSignOn" />
        -->

        <!-- Access log processes all example.
             Documentation at: /docs/config/valve.html
             Note: The pattern used is equivalent to using pattern="common" -->
        <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
               prefix="localhost_access_log." suffix=".txt"
               pattern="%h %l %u %t "%r" %s %b" />

      </Host>
    </Engine>
  </Service>
</Server>

Events:  <none>

创建pod将configMap中的配置挂载到pod中,

[root@node-1 pod]# vi centos_tomcat.yaml 
apiVersion: apps/v1
kind: Deployment
metadata:
  name: centos
  labels:
    app: centos
spec:
  replicas: 1
  selector:
    matchLabels:
      app: centos
  template:
    metadata:
      labels:
        app: centos
    spec:
      containers:
      - name: centos
        image: centos:7.4-tomcat
        imagePullPolicy: Never
        command: [ "/bin/bash", "-c", "--" ]
        args: [ "while true; do sleep 30; done;" ]
        volumeMounts:
        - name: iso
          mountPath: /media/cdrom
        - name: serverxml
          mountPath: /etc/tomcat/log4j1.properties
          subPath: log4j.properties
        - name: serverxml
          mountPath: /etc/tomcat/server.xml
          subPath: server.xml
      volumes:
      - name: iso
        hostPath:
          path: /mnt
      - name: serverxml
        configMap:
          name: tomcat-config
          items:
          - key: log4j.properties
            path: log4j.properties
          - key: server.xml
            path: server.xml
      nodeSelector:
        path: iso

查看结果:

[root@centos-6d8f95c859-v9lh2 /]# ll /etc/tomcat/
total 220
drwxrwxr-x 3 root tomcat     23 Jan 27 09:15 Catalina
-rw-r--r-- 1 root tomcat  13443 Aug  7  2017 catalina.policy
-rw-r--r-- 1 root tomcat   6496 Aug  7  2017 catalina.properties
drwxr-xr-x 2 root tomcat     20 Jan 27 09:15 conf.d
-rw-r--r-- 1 root tomcat   1394 Aug  7  2017 context.xml
-rw-r--r-- 1 root tomcat    547 Aug  7  2017 log4j.properties
-rw-r--r-- 1 root root      547 Jan 27 14:42 log4j1.properties
-rw-r--r-- 1 root tomcat   3288 Aug  7  2017 logging.properties
-rw-r--r-- 1 root root     6613 Jan 27 14:42 server.xml
-rw-r----- 1 root tomcat   2418 Aug  7  2017 tomcat-users.xml
-rw-r--r-- 1 root tomcat   1651 Aug  7  2017 tomcat.conf
-rw-r--r-- 1 root tomcat 167655 Aug  7  2017 web.xml

我们将configmap的logging的配置文件添加一个标记:

[root@node-1 tomcat]# cat log4j.properties 
#flag
log4j.rootLogger=debug, R 
log4j.appender.R=org.apache.log4j.RollingFileAppender 
log4j.appender.R.File=${catalina.home}/logs/tomcat.log 
log4j.appender.R.MaxFileSize=10MB 
log4j.appender.R.MaxBackupIndex=10 
log4j.appender.R.layout=org.apache.log4j.PatternLayout 
log4j.appender.R.layout.ConversionPattern=%p %t %c - %m%n 
log4j.logger.org.apache.catalina=DEBUG, R
log4j.logger.org.apache.catalina.core.ContainerBase.[Catalina].[localhost]=DEBUG, R
log4j.logger.org.apache.catalina.core=DEBUG, R
log4j.logger.org.apache.catalina.session=DEBUG, R

当前方式不支持热更新,所以需要删除deployment,重新创建.

[root@node-1 pod]# kubectl delete deployments.apps centos 
deployment.apps "centos" deleted
[root@node-1 pod]# kubectl create -f centos_tomcat.yaml 
deployment.apps/centos created
[root@node-1 pod]# 
[root@node-1 pod]# 
[root@node-1 pod]# kubectl get pod
NAME                      READY   STATUS        RESTARTS   AGE
centos-6d8f95c859-r4xw2   1/1     Running       0          10s
centos-6d8f95c859-v9lh2   1/1     Terminating   1          17m
[root@node-1 pod]# kubectl get pod
NAME                      READY   STATUS        RESTARTS   AGE
centos-6d8f95c859-r4xw2   1/1     Running       0          12s
centos-6d8f95c859-v9lh2   1/1     Terminating   1          17m
[root@node-1 pod]# kubectl exec -it centos-6d8f95c859-r4xw2 /bin/bash
[root@centos-6d8f95c859-r4xw2 /]# cd /etc/tomcat/
[root@centos-6d8f95c859-r4xw2 tomcat]# ll
total 220
drwxrwxr-x 3 root tomcat     23 Jan 27 09:15 Catalina
-rw-r--r-- 1 root tomcat  13443 Aug  7  2017 catalina.policy
-rw-r--r-- 1 root tomcat   6496 Aug  7  2017 catalina.properties
drwxr-xr-x 2 root tomcat     20 Jan 27 09:15 conf.d
-rw-r--r-- 1 root tomcat   1394 Aug  7  2017 context.xml
-rw-r--r-- 1 root tomcat    547 Aug  7  2017 log4j.properties
-rw-r--r-- 1 root root      553 Jan 27 14:59 log4j1.properties
-rw-r--r-- 1 root tomcat   3288 Aug  7  2017 logging.properties
-rw-r--r-- 1 root root     6613 Jan 27 14:59 server.xml
-rw-r----- 1 root tomcat   2418 Aug  7  2017 tomcat-users.xml
-rw-r--r-- 1 root tomcat   1651 Aug  7  2017 tomcat.conf
-rw-r--r-- 1 root tomcat 167655 Aug  7  2017 web.xml
[root@centos-6d8f95c859-r4xw2 tomcat]# cat log4j1.properties 
#flag
log4j.rootLogger=debug, R 
log4j.appender.R=org.apache.log4j.RollingFileAppender 
log4j.appender.R.File=${catalina.home}/logs/tomcat.log 
log4j.appender.R.MaxFileSize=10MB 
log4j.appender.R.MaxBackupIndex=10 
log4j.appender.R.layout=org.apache.log4j.PatternLayout 
log4j.appender.R.layout.ConversionPattern=%p %t %c - %m%n 
log4j.logger.org.apache.catalina=DEBUG, R
log4j.logger.org.apache.catalina.core.ContainerBase.[Catalina].[localhost]=DEBUG, R
log4j.logger.org.apache.catalina.core=DEBUG, R
log4j.logger.org.apache.catalina.session=DEBUG, R

很晚,睡觉…