把H2数据库从jar包部署到Kubernetes,并解决Ingress不支持TCP的问题


1 前言

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H2 Database是一个优秀的数据库,又小又方便,支持内存和文件形式,经常会在测试POC(proof of concept)开发环境用到它。在Springboot的许多应用中,也是内置了H2数据库,很常用。接下来我们来一步步把它推上k8s,让它坐上一个不一样的位置。

建议阅读下面文章以帮助理解:

Kubernetes用Helm安装Ingress并踩一下使用的坑

容器技术相关文章

2 本地jar包运行

2.1 下载和启动

下载官网jar包如下:

$ curl http://www.h2database.com/h2-2019-03-13.zip -o h2-2019-03-13.zip

解压:

$ unzip h2-2019-03-13.zip

启动H2数据库

$ java -cp h2/bin/h2*.jar org.h2.tools.Server -ifNotExists
TCP server running at tcp://localhost:9092 (only local connections)
PG server running at pg://localhost:5435 (only local connections)
Web Console server running at http://localhost:8082 (others can connect)

如果需要修改配置,如端口号、数据存储目录,可以在启动时添加参数:

java -cp h2/bin/h2*.jar org.h2.tools.Server -ifNotExists \
    -web -webAllowOthers -webPort 8082 \
    -tcp -tcpAllowOthers -tcpPort 9092 \
    -baseDir ${DATA_DIR} ${H2_OPTIONS}

2.2 配置连接

成功启动后访问http://localhost:8082就能登陆控制台了。如下:

Driver Classorg.h2.Driver,驱动类;

JDBC URLjdbc:h2:mem:pkslow,使用内存数据库,数据库名为pkslow

账号密码设置为admin/123456

设置完成后,点击连接即可创建数据库。

如果我们把JDBC URL改为jdbc:h2:file:~/pkslow,就是以文件形式存在,这样能把数据持久化,所以我们采取这种方式。这里就会在~目录,即${HOME}目录生成文件pkslow.mv.db以保存数据。还有文件~/.h2.server.properties

更多URL的配置方法如下表:

Topic URL Format and Examples
[Embedded (local) connection](http://www.h2database.com/html/features.html#embedded_databases) jdbc:h2:[file:][] jdbc:h2:~/test jdbc:h2:file:/data/sample jdbc:h2:file:C:/data/sample (Windows only)
[In-memory (private)](http://www.h2database.com/html/features.html#in_memory_databases) jdbc:h2:mem:
[In-memory (named)](http://www.h2database.com/html/features.html#in_memory_databases) jdbc:h2:mem: jdbc:h2:mem:test_mem
[Server mode (remote connections) using TCP/IP](http://www.h2database.com/html/tutorial.html#using_server) jdbc:h2:tcp://[:]/[] jdbc:h2:tcp://localhost/~/test jdbc:h2:tcp://dbserv:8084/~/sample jdbc:h2:tcp://localhost/mem:test
[Server mode (remote connections) using TLS](http://www.h2database.com/html/advanced.html#tls_connections) jdbc:h2:ssl://[:]/[] jdbc:h2:ssl://localhost:8085/~/sample;
[Using encrypted files](http://www.h2database.com/html/features.html#file_encryption) jdbc:h2:;CIPHER=AES jdbc:h2:ssl://localhost/~/test;CIPHER=AES jdbc:h2:file:~/secure;CIPHER=AES
[File locking methods](http://www.h2database.com/html/features.html#database_file_locking) jdbc:h2:;FILE_LOCK={FILE|SOCKET|NO} jdbc:h2:file:~/private;CIPHER=AES;FILE_LOCK=SOCKET
[Only open if it already exists](http://www.h2database.com/html/features.html#database_only_if_exists) jdbc:h2:;IFEXISTS=TRUE jdbc:h2:file:~/sample;IFEXISTS=TRUE
[Don't close the database when the VM exits](http://www.h2database.com/html/features.html#do_not_close_on_exit) jdbc:h2:;DB_CLOSE_ON_EXIT=FALSE
[Execute SQL on connection](http://www.h2database.com/html/features.html#execute_sql_on_connection) jdbc:h2:;INIT=RUNSCRIPT FROM '~/create.sql' jdbc:h2:file:~/sample;INIT=RUNSCRIPT FROM '~/create.sql';RUNSCRIPT FROM '~/populate.sql'
[User name and/or password](http://www.h2database.com/html/advanced.html#passwords) jdbc:h2:[;USER=][;PASSWORD=] jdbc:h2:file:~/sample;USER=sa;PASSWORD=123
[Debug trace settings](http://www.h2database.com/html/features.html#trace_options) jdbc:h2:;TRACE_LEVEL_FILE= jdbc:h2:file:~/sample;TRACE_LEVEL_FILE=3
[Ignore unknown settings](http://www.h2database.com/html/features.html#ignore_unknown_settings) jdbc:h2:;IGNORE_UNKNOWN_SETTINGS=TRUE
[Custom file access mode](http://www.h2database.com/html/features.html#custom_access_mode) jdbc:h2:;ACCESS_MODE_DATA=rws
[Database in a zip file](http://www.h2database.com/html/features.html#database_in_zip) jdbc:h2:zip:!/ jdbc:h2:zip:~/db.zip!/test
[Compatibility mode](http://www.h2database.com/html/features.html#compatibility) jdbc:h2:;MODE= jdbc:h2:~/test;MODE=MYSQL;DATABASE_TO_LOWER=TRUE
[Auto-reconnect](http://www.h2database.com/html/features.html#auto_reconnect) jdbc:h2:;AUTO_RECONNECT=TRUE jdbc:h2:tcp://localhost/~/test;AUTO_RECONNECT=TRUE
[Automatic mixed mode](http://www.h2database.com/html/features.html#auto_mixed_mode) jdbc:h2:;AUTO_SERVER=TRUE jdbc:h2:~/test;AUTO_SERVER=TRUE
[Page size](http://www.h2database.com/html/features.html#page_size) jdbc:h2:;PAGE_SIZE=512
[Changing other settings](http://www.h2database.com/html/features.html#other_settings) jdbc:h2:;=[;=...] jdbc:h2:file:~/sample;TRACE_LEVEL_SYSTEM_OUT=3

3 在Docker运行

3.1 创建镜像并启动

编写Dockerfile文件:

FROM adoptopenjdk/openjdk8-openj9:latest
COPY h2/ h2/
ENV DATA_DIR /opt/h2-data
RUN mkdir -p ${DATA_DIR}
EXPOSE 8082 9092
ENTRYPOINT java -cp h2/bin/h2-1.4.199.jar org.h2.tools.Server -ifNotExists \
    -web -webAllowOthers \
    -tcp -tcpAllowOthers \
    -baseDir ${DATA_DIR} ${H2_OPTIONS}

这里把数据存储文件放在/opt/h2-data目录上,使用默认端口,所以只对外暴露8082/9092端口。

通过Dockerfile创建镜像:

$ docker build -t h2:1.4.199 .

启动Docker容器:

$ docker run -itd --name h2 -p 8082:8082 -p 9092:9092 h2:1.4.199

3.2 通过Web和TCP方式连接

3.2.1 Web界面连接

成功启动后,访问http://localhost:8082配置连接如下:

进入容器,查看在/opt/h2-data目录生成了存储文件:

$ docker exec -it h2 /bin/bash
root@0121e369b933:/opt/h2-data# l
test.mv.db

3.2.2 TCP方式连接

通过IDEA配置连接H2时要注意路径,通过TCP方式,不用加baseDir,配置为jdbc:h2:tcp://localhost:9092/test。如果要加,应该配置为jdbc:h2:tcp://localhost:9092//opt/h2-data/test

4 部署在Kubernetes上运行

4.1 部署上Kubernetes看看

4.1.1 创建PersistentVolumeClaim

PersistentVolumeClaim,简称PVC,是Kubernetes用于存储的单元,为了可以使H2的数据持久化,在Pod死掉后重启数据不丢失,我们来创建对应的PVC

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: h2-db
  labels:
    app: h2-db
  annotations:
    volume.alpha.kubernetes.io/storage-class: default
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 0.05Gi

这里空间只给0.05G,反正实验为主,不作其它用途。

4.1.2 创建Deployment

这里最关键的是要注意PVC的配置:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: h2-db
  labels:
    app: h2-db
spec:
  replicas: 1
  selector:
    matchLabels:
      app: h2-db
  template:
    metadata:
      labels:
        app: h2-db
    spec:
      containers:
      - image: h2:1.4.199
        name: h2-db
        ports:
          - containerPort: 8082
            name: h2-web
          - containerPort: 9092
            name: h2-tcp
        volumeMounts:
          - name: data
            mountPath: /opt/h2-data
      volumes:
      - name: data
        persistentVolumeClaim:
          claimName: h2-db

mountPath对应的是之前在制作Docker镜像时指定的路径。

4.1.3 创建Service和Ingress

ServiceIngress对应的yaml文件如下:

apiVersion: v1
kind: Service
metadata:
  name: h2-db
  labels:
    app: h2-db
spec:
  ports:
    - port: 8082
      name: web
    - port: 9092
      name: tcp
  selector:
    app: h2-db
---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: h2-ingress
  annotations:
    kubernetes.io/ingress.class: nginx
spec:
  rules:
    - http:
        paths:
          - path: /
            backend:
              serviceName: h2-db
              servicePort: 8082
      host: h2-web.localhost
    - http:
        paths:
          - path: /
            backend:
              serviceName: h2-db
              servicePort: 9092
      host: h2-tcp.localhost

4.1.4 访问

Web方式简单,通过访问http://h2-web.localhost/配置连接即可。

TCP方式就麻烦了,无论如何配置,死活连不上。具体原因接下来继续讨论。

4.2 让Ingress支持TCP

之前TCP连不上的原因是Ingress是不支持TCP路由转发的,虽然Ingress是基于Nginx,而Nginx又可以转发代理TCP/UDP。那就来探索一番吧。

4.2.1 修改nginx-ingress-controller

为了让它支持TCP/UDP,我们要修改Ingress-Controller,在它的配置文件增加参数:

- --tcp-services-configmap=$(POD_NAMESPACE)/tcp-services
- --udp-services-configmap=$(POD_NAMESPACE)/udp-services

在下面内容中插入:

containers:
- args:
  - /nginx-ingress-controller
  - --default-backend-service=default/pki-nginx-ingress-default-backend
  - --election-id=ingress-controller-leader
  - --ingress-class=nginx
  - --configmap=default/pki-nginx-ingress-controller
  - --tcp-services-configmap=$(POD_NAMESPACE)/tcp-services
  - --udp-services-configmap=$(POD_NAMESPACE)/udp-services

4.2.2 添加tcp-services config

上面的Controller指定了tcp-servicesConfigMap,那我们就添加上:

kind: ConfigMap
apiVersion: v1
metadata:
  name: tcp-services
  namespace: default
data:
  "9092": default/h2-db:9092

其中,"9092": default/h2-db:9092表示:<Nginx port>: <namespace/service name>:<service port>:[PROXY]:[PROXY],我们这样配置相当于把Nginx9092端口,指向H29092端口。

4.2.3 修改Ingress Service的端口

在只有http/https的基础上,增加H2配置:

spec:
  externalTrafficPolicy: Cluster
  ports:
  - name: http
    nodePort: 32231
    port: 80
    protocol: TCP
    targetPort: http
  - name: https
    nodePort: 30370
    port: 443
    protocol: TCP
    targetPort: https
  - name: h2-tcp
    nodePort: 30371
    port: 9092
    protocol: TCP
    targetPort: 9092

4.2.4 连接使用

完成以上步骤后,就可以连接了,如下:

配置后连接成功。

5 总结

至此,我们一步步从jar包到部署H2DatabaseKubernetes,希望大家能从整个过程学到一些知识吧。我们解决了之前安装Ingress不支持TCP的问题,但始终不是一个太好的方案。如果我们把连接数据库的应用都部署在Kubernetes上,那就没有必要把H2TCP暴露出去了。


原文链接:https://www.cnblogs.com/larrydpk/p/13496644.html