Docker进阶

Eccentric 收录于运维

2021-04-09 约 4779 字预计阅读 10 分钟次阅读

Docker Compose

Using Compose is basically a three-step process:

Define your app’s environment with a Dockerfile so it can be reproduced anywhere.
Define the services that make up your app in docker-compose.yml so they can be run together in an isolated environment.
Run docker compose up and the Docker compose command starts and runs your entire app. You can alternatively run docker-compose up using the docker-compose binary.

Compose是官方的开源项目，需要安装，

Dockerfile可以让程序在任何地方运行，但是现在有一个web服务，但是它又需要redis、MySQL、nginx等多个容器，一个一个启动就会十分麻烦。

Compose例子：

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15


version: "3.9"  # optional since v1.27.0
services:
  web:
    build: .
    ports:
      - "5000:5000"
    volumes:
      - .:/code
      - logvolume01:/var/log
    links:
      - redis
  redis:
    image: redis
volumes:
  logvolume01: {}

安装Compose

1、下载：

1
2
3


sudo curl -L "https://github.com/docker/compose/releases/download/1.29.0/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose

sudo curl -L "https://get.daocloud.io/docker/compose/releases/download/1.29.0/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose

2、授权

1

sudo chmod +x /usr/local/bin/docker-compose

3、全局使用

1
2
3
4
5


[root@node4 /]# docker-compose version
docker-compose version 1.29.0, build 07737305
docker-py version: 5.0.0
CPython version: 3.7.10
OpenSSL version: OpenSSL 1.1.0l  10 Sep 2019

快速体验

Step 1: 创建应用

Define the application dependencies.

Create a directory for the project(创建目录):
1 2

$ mkdir composetest $ cd composetest

Create a file called app.py in your project directory and paste this in（创建python文件）:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23


import time

import redis
from flask import Flask

app = Flask(__name__)
cache = redis.Redis(host='redis', port=6379)

def get_hit_count():
    retries = 5
    while True:
        try:
            return cache.incr('hits')
        except redis.exceptions.ConnectionError as exc:
            if retries == 0:
                raise exc
            retries -= 1
            time.sleep(0.5)

@app.route('/')
def hello():
    count = get_hit_count()
    return 'Hello World! I have been seen {} times.\n'.format(count)

在这个例子中, redis 是应用网络中redis的容器名称. 使用端口, 6379.

注意get_hit_coun函数的编写方式。这个基本的重试循环允许我们在redis服务不可用时多次尝试请求。当应用程序上线时，这在启动时很有用，但如果在应用程序的生命周期内需要随时重新启动Redis服务，也会使我们的应用程序更有弹性。在集群中，这也有助于处理节点之间的瞬时连接中断。

创建 requirements.txt 文件:
1 2

flask redis

Step 2: 编写Dockerfile

这一步将编写dockerfile并build image ,这个镜像包含了python所需要的环境

Dockerfile 文件:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10


FROM python:3.7-alpine
WORKDIR /code
ENV FLASK_APP=app.py
ENV FLASK_RUN_HOST=0.0.0.0
RUN apk add --no-cache gcc musl-dev linux-headers
COPY requirements.txt requirements.txt
RUN pip install -r requirements.txt
EXPOSE 5000
COPY . .
CMD ["flask", "run"]

This tells Docker to:

Build an image starting with the Python 3.7 image.
Set the working directory to /code.
Set environment variables used by the flask command.
Install gcc and other dependencies
Copy requirements.txt and install the Python dependencies.
Add metadata to the image to describe that the container is listening on port 5000
Copy the current directory . in the project to the workdir . in the image.
Set the default command for the container to flask run.

For more information on how to write Dockerfiles, see the Docker user guide and the Dockerfile reference.

Step 3: 在Compose文件中定义Service

创建 docker-compose.yml 文件:

1
2
3
4
5
6
7
8


version: "3.9"
services:
  web:
    build: .
    ports:
      - "5000:5000"
  redis:
    image: "redis:alpine"

这个Compose声明了两个service: web and redis.

1
2
3
4
5
6


[root@node4 composetest]# ll
总用量 16
-rw-r--r--. 1 root root 514 4月   9 16:48 app.py
-rw-r--r--. 1 root root 111 4月   9 17:00 docker-compose.yml
-rw-r--r--. 1 root root 252 4月   9 16:50 Dockerfile
-rw-r--r--. 1 root root  12 4月   9 16:49 requirements.txt

Step 4: 用Compose启动多个容器

1

docker-compose up

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14


[root@node4 ~]# docker ps
CONTAINER ID   IMAGE             COMMAND                  CREATED          STATUS          PORTS                    NAMES
9a28f238ee73   composetest_web   "flask run"              34 seconds ago   Up 32 seconds   0.0.0.0:5000->5000/tcp   composetest_web_1
e4cb9836d38d   redis:alpine      "docker-entrypoint.s…"   34 seconds ago   Up 32 seconds   6379/tcp                 composetest_redis_1
[root@node4 ~]# curl localhost:5000
Hello World! I have been seen 1 times.
[root@node4 ~]# curl localhost:5000
Hello World! I have been seen 2 times.
[root@node4 ~]# curl localhost:5000
Hello World! I have been seen 3 times.
[root@node4 ~]# curl localhost:5000
Hello World! I have been seen 4 times.
[root@node4 ~]# curl localhost:5000
Hello World! I have been seen 5 times.

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50


[root@node4 ~]# docker network inspect composetest_default
[
    {
        "Name": "composetest_default",
        "Id": "25ec9a55f82b6ff2c9b190c911cf6a89ce998759b912c3f2dbf5c2849a6c89d5",
        "Created": "2021-04-09T17:01:45.524551071+08:00",
        "Scope": "local",
        "Driver": "bridge",
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": null,
            "Config": [
                {
                    "Subnet": "172.18.0.0/16",
                    "Gateway": "172.18.0.1"
                }
            ]
        },
        "Internal": false,
        "Attachable": true,
        "Ingress": false,
        "ConfigFrom": {
            "Network": ""
        },
        "ConfigOnly": false,
        "Containers": {
            "9a28f238ee7334688d70f20a2838cbcea964bb3f1282b99b4c787b61370bd202": {
                "Name": "composetest_web_1",
                "EndpointID": "920c033116c19419b0e2807f75284d768436cb272735642b7e8257f9564d9e45",
                "MacAddress": "02:42:ac:12:00:03",
                "IPv4Address": "172.18.0.3/16",
                "IPv6Address": ""
            },
            "e4cb9836d38deb2d2dbd4211106dd2364ace9f97ab5e8827736fc7d39b5ba166": {
                "Name": "composetest_redis_1",
                "EndpointID": "7f359906cf87650c9ef25939d25c7cfe070ac1135855ff888f1b7a881682aa31",
                "MacAddress": "02:42:ac:12:00:02",
                "IPv4Address": "172.18.0.2/16",
                "IPv6Address": ""
            }
        },
        "Options": {},
        "Labels": {
            "com.docker.compose.network": "default",
            "com.docker.compose.project": "composetest",
            "com.docker.compose.version": "1.29.0"
        }
    }
]

流程：

创建网络
执行docker-compose.yml
启动服务

默认规则：

默认服务名（容器名）：文件夹名_服务名__num num为副本数量，因为服务不可能只有一个，弹性扩容，高可用
docker images 会自动pull所需images
docker network ls 自动生成网络（同一个网络通过service名称连通） composetest_自定义网络名称

停止compose：

1
2
3
4
5


docker-compose down    ctrl+c
#一键停止所有容器
^CGracefully stopping... (press Ctrl+C again to force)
Stopping composetest_web_1   ... 
Stopping composetest_web_1   ... done

yml文件编写规则

compose文件编写参考：https://docs.docker.com/compose/compose-file/compose-file-v3/

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17


#第一层
version: ''  #向下兼容
#第二层
service:   #服务
	服务1:
		#服务配置
		images:
		build:
		network:
		...
	服务2:
		...
#第三层
volumes:
network:
config:
...

多看官方文档，开源项目的compose

部署Woedpress项目

1、创建目录：

1
2


mkdir my_wordpress
 cd my_wordpress/

2、创建compose文件：

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30


nano docker-compose.yml

version: "3.9"
    
services:
  db:
    image: mysql:5.7
    volumes:
      - db_data:/var/lib/mysql
    restart: always
    environment:
      MYSQL_ROOT_PASSWORD: somewordpress
      MYSQL_DATABASE: wordpress
      MYSQL_USER: wordpress
      MYSQL_PASSWORD: wordpress
    
  wordpress:
    depends_on:
      - db
    image: wordpress:latest
    ports:
      - "8000:80"
    restart: always
    environment:
      WORDPRESS_DB_HOST: db:3306
      WORDPRESS_DB_USER: wordpress
      WORDPRESS_DB_PASSWORD: wordpress
      WORDPRESS_DB_NAME: wordpress
volumes:
  db_data: {}

3、启动：

1

docker-compose up -d      #后台启动

1
2
3
4


[root@node4 my_wordpress]# docker ps 
CONTAINER ID   IMAGE              COMMAND                  CREATED              STATUS              PORTS                  NAMES
a56f5f6a9eb6   wordpress:latest   "docker-entrypoint.s…"   About a minute ago   Up About a minute   0.0.0.0:8000->80/tcp   my_wordpress_wordpress_1
63f261196b58   mysql:5.7          "docker-entrypoint.s…"   About a minute ago   Up About a minute   3306/tcp, 33060/tcp    my_wordpress_db_1

All are easy!!!!

实战：自己编写服务上线

1、编写自己的服务：

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18


package com.example.democompose.Controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {
    @Autowired
    StringRedisTemplate redisTemplate;
    @GetMapping("/hello")
    public String hello(){
        Long views=redisTemplate.opsForValue().increment("views");
        return "hello,这是第"+views+"次访问";

    }
}

1
2


server.port=8080
spring.redis.host=redis

2、编写Dockerfile文件：

1
2
3
4
5
6
7
8
9


FROM java:8

COPY *.jar /app.jar

CMD ["--server.port=8080"]

EXPOSE 8888

ENTRYPOINT ["java","-jar","/app.jar"]

3、编写docker-compose.yml文件

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11


version: '3.8'
services:
  myapp:
    build: .
    image: mytextappcompose
    depends_on:
      - redis
    ports:
      - "8080:8080"
  redis:
    image: "library/redis:alpine"

4、打jar包上传服务器

5、运行服务：

1
2
3


docker-compose up -d

docker-compose up --build     #重新构建

Docker Swarm

搭建集群

集群—–4台服务器（一主三从）

4台机器安装Docker(Xshell窗口右键：发送键输入到所有会话):

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14


sudo yum install -y yum-utils
# 3、设置镜像仓
sudo yum-config-manager \
    --add-repo \
    http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo	# 默认是国外的 可换国内

yum makecache fast

# 4、安装相关的额
sudo yum install docker-ce docker-ce-cli containerd.io

# 5、启动
sudo systemctl start docker
docker version

1
2
3
4


noe2	192.168.80.133
noe3	192.168.80.134
node4	192.168.80.135
test	192.168.80.136

初始化管理节点node2:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11


# 初始化一个manager节点
docker swarm init --advertise-addr 192.168.80.133

[root@node2 network-scripts]# docker swarm init --advertise-addr 192.168.80.133
Swarm initialized: current node (a5gz7qpsgbjolzgzg1tlaj8lh) is now a manager.

To add a worker to this swarm, run the following command:

    docker swarm join --token SWMTKN-1-4ga8o43bv28liq5q27e27deq5513t3efpl1nq7mlskyp3dulgn-e252fso8bl6zbrqtywqusrexd 192.168.80.133:2377

To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.

docker swarm join加入一个节点：

1
2
3


#获取令牌
docker swarm join-token manager		#管理节点
docker swarm join-token worker		#工作节点

初始化工作节点node3:

1
2


[root@node3 ~]# docker swarm join --token SWMTKN-1-4ga8o43bv28liq5q27e27deq5513t3efpl1nq7mlskyp3dulgn-e252fso8bl6zbrqtywqusrexd 192.168.80.133:2377
This node joined a swarm as a worker.

查看现有集群状态：

1
2
3
4


[root@node2 /]# docker node ls
ID                            HOSTNAME   STATUS    AVAILABILITY   MANAGER STATUS   ENGINE VERSION
a5gz7qpsgbjolzgzg1tlaj8lh *   node2      Ready     Active         Leader           20.10.5
e2hlgfd1v4xk7azjp27ce3fcy     node3      Ready     Active                          20.10.5

初始化工作节点node4:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10


[root@node2 /]# docker swarm join-token worker
To add a worker to this swarm, run the following command:

    docker swarm join --token SWMTKN-1-4ga8o43bv28liq5q27e27deq5513t3efpl1nq7mlskyp3dulgn-e252fso8bl6zbrqtywqusrexd 192.168.80.133:2377
    
[root@node2 /]# docker node ls
ID                            HOSTNAME   STATUS    AVAILABILITY   MANAGER STATUS   ENGINE VERSION
a5gz7qpsgbjolzgzg1tlaj8lh *   node2      Ready     Active         Leader           20.10.5
e2hlgfd1v4xk7azjp27ce3fcy     node3      Ready     Active                          20.10.5
6ne9u5knznm8ei0c5uz7znka9     node4      Ready     Active                          20.10.5

初始化管理节点test:

1
2


docker swarm join-token manager
docker node ls

1
2


[root@localhost ~]# docker swarm join --token SWMTKN-1-4ga8o43bv28liq5q27e27deq5513t3efpl1nq7mlskyp3dulgn-66whvjsogw3qsqozb79oprffr 192.168.80.133:2377
Error response from daemon: manager stopped: can't initialize raft node: rpc error: code = Unknown desc = could not connect to prospective new cluster member using its advertised address: rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 192.168.80.136:2377: connect: no route to host"

试了好多次发现总是加入管理节点错误，一开始怀疑自己网络通信问题，后来网上无脑抄袭一致认为代理问题：

最终发现是自己新建的虚拟机test防火墙没有关:

1
2
3
4
5
6


#查看防火墙状态
systemctl status firewalld.service
#停止防火墙
systemctl stop firewalld.service
#永久停止
systemctl disable firewalld.service

Raft协议

现在：双主双从，假设一个节点挂了，其他节点是否可用？？

Raft协议：保证大多数节点存活集群才可用，至少大于1台，集群至少大于3台！！

实验：

1、将node2管理节点停止，宕机，另外一个管理节点也不能用了

1

systemctl stop docker

在test管理节点查看集群，发现不可用：

2、重新启动node2:

1

systemctl start docker

发现leader节点变了：

3、工作节点node3离开：

1
2


docker swarm --help
docker swarm leave

4、三主一工作：

1
2
3
4
5
6
7


docker swarm join-token manager

jb30cv8ej8xjokjc1cu5l8kjo     localhost.localdomain   Ready     Active         Leader           20.10.5
a5gz7qpsgbjolzgzg1tlaj8lh *   node2                   Ready     Active         Reachable        20.10.5
nmhr2t2b5cgy4l64bcwl0mxjt     node3                   Ready     Active         Reachable        20.10.5
e2hlgfd1v4xk7azjp27ce3fcy     node3                   Down      Active                          20.10.5
6ne9u5knznm8ei0c5uz7znka9     node4                   Ready     Active                          20.10.5

现在就是3台作为管理节点：

5、停掉Leader(test)：

现在Leader是test节点，停掉：

在node2查看集群状态,发现node3变成了leader，集群任然可用

6、大多数存活可用

现在只有两个管理节点（node2/node3），一个工作节点(node4)，如果再停止一个管理节点，那就无法使用了：

1
2


[root@node3 ~]# docker node ls
Error response from daemon: rpc error: code = Unknown desc = The swarm does not have a leader. It's possible that too few managers are online. Make sure more than half of the managers are online.

大多数管理节点存活才可用

集群部署应用、弹性、扩缩容

以后告别docker run

集群：高可用，web->redis(分布在三台不同主机上，服务副本，挂了一个没事，其他可用)

容器=》服务=》副本

1
2


docker run    # 容器启动，不具备扩缩容功能
docker service   #服务，具备扩缩容、滚动跟新、灰度发布

服务部署

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18


#前提是swarm搭建好
#在node2中创建服务
docker service create -p 8888:80 --name mynginx nginx
docker service ls
docker service ps mynginx
docker service inspect mynginx

[root@node2 ~]# docker service ps mynginx
ID             NAME        IMAGE          NODE      DESIRED STATE   CURRENT STATE            ERROR     PORTS
ndtmy83nj0v3   mynginx.1   nginx:latest   node3     Running         Running 34 seconds ago             
[root@node2 ~]# docker service ls
ID             NAME      MODE         REPLICAS   IMAGE          PORTS
iv9jcn74r0uj   mynginx   replicated   1/1        nginx:latest   *:8888->80/tcp
# 服务副本只有一个，并且服务运行在node3主机上

[root@node3 ~]# docker ps
CONTAINER ID   IMAGE          COMMAND                  CREATED         STATUS         PORTS     NAMES
a92bf0b74b83   nginx:latest   "/docker-entrypoint.…"   4 minutes ago   Up 4 minutes   80/tcp    mynginx.1.ndtmy83nj0v3oathgaleiw37v

现在服务只随机创建了一个服务，在node3主机上，假如现在访问量加大，需要扩容：

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14


# 创建3个副本
docker service update --replicas 3 mynginx

[root@node3 ~]# docker service update --replicas 3 mynginx
mynginx
overall progress: 3 out of 3 tasks 
1/3: running   [==================================================>] 
2/3: running   [==================================================>] 
3/3: running   [==================================================>] 
verify: Service converged 
[root@node3 ~]# docker service ls
ID             NAME      MODE         REPLICAS   IMAGE          PORTS
iv9jcn74r0uj   mynginx   replicated   3/3        nginx:latest   *:8888->80/tcp
[root@node3 ~]# docker service inspect mynginx

此时三个服务副本在node3、node4、test主机上

在集群中的任意一个节点都可访问，服务可以有多个副本来实现高可用：

但是现在通过node3IP无法访问服务，其他正常

大无语事件来了，有彩蛋:

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22


#如果把副本数量讲到1个会怎么样？？降！！！

[root@node3 ~]# docker service update --replicas 1 mynginx
mynginx
overall progress: 1 out of 1 tasks 
1/1: running   [==================================================>] 
verify: Service converged 
#那就是只有这个一个副本？？？（bug）

[root@node3 ~]# docker ps
CONTAINER ID   IMAGE          COMMAND                  CREATED          STATUS          PORTS     NAMES
a92bf0b74b83   nginx:latest   "/docker-entrypoint.…"   40 minutes ago   Up 40 minutes   80/tcp    mynginx.1.ndtmy83nj0v3oathgaleiw37v
#发现还是访问不了，查看日志，发现他的日志启动一半，少了许多日志，那就重启

[root@node3 ~]# docker restart mynginx.1.ndtmy83nj0v3oathgaleiw37v
mynginx.1.ndtmy83nj0v3oathgaleiw37v
[root@node3 ~]# docker ps
CONTAINER ID   IMAGE          COMMAND                  CREATED          STATUS              PORTS     NAMES
a92bf0b74b83   nginx:latest   "/docker-entrypoint.…"   42 minutes ago   Up About a minute   80/tcp    mynginx.1.ndtmy83nj0v3oathgaleiw37v
[root@node3 ~]# docker service ls
ID             NAME      MODE         REPLICAS   IMAGE          PORTS
iv9jcn74r0uj   mynginx   replicated   1/1        nginx:latest   *:8888->80/tcp

但是我又发现，怎么会有两个：

1
2
3
4
5
6
7


[root@node2 ~]# docker ps
CONTAINER ID   IMAGE          COMMAND                  CREATED          STATUS          PORTS     NAMES
2bc639d336dd   nginx:latest   "/docker-entrypoint.…"   13 minutes ago   Up 13 minutes   80/tcp    mynginx.1.wgk7pwm0mm7zs6fawmb7p6otf

[root@node3 ~]# docker ps
CONTAINER ID   IMAGE          COMMAND                  CREATED          STATUS          PORTS     NAMES
a92bf0b74b83   nginx:latest   "/docker-entrypoint.…"   55 minutes ago   Up 14 minutes   80/tcp    mynginx.1.ndtmy83nj0v3oathgaleiw37v

我把其中一个关掉还是不能访问，此时通过mynginx信息发现如下错误：

1
2
3
4
5


[root@node2 ~]# docker service ps  mynginx
ID             NAME            IMAGE          NODE      DESIRED STATE   CURRENT STATE            ERROR                         PORTS
x8advkit107e   mynginx.1       nginx:latest   node4     Running         Running 6 minutes ago                                  
wgk7pwm0mm7z    \_ mynginx.1   nginx:latest   node2     Shutdown        Complete 6 minutes ago                                 
ndtmy83nj0v3    \_ mynginx.1   nginx:latest   node3     Shutdown        Failed 25 minutes ago    "task: non-zero exit (137)"

那就只能重来一遍：

1
2
3
4
5
6
7


docker service rm mynginx
docker service create -p 8888:80 --replicas 3 --name mynginxtest nginx
[root@node2 ~]# docker service ps  mynginxtest
ID             NAME            IMAGE          NODE                    DESIRED STATE   CURRENT STATE            ERROR     PORTS
fultv05jwsbm   mynginxtest.1   nginx:latest   localhost.localdomain   Running         Running 15 seconds ago             
yikbwlzinhd5   mynginxtest.2   nginx:latest   node3                   Running         Running 17 seconds ago             
f5cljf1f6d73   mynginxtest.3   nginx:latest   node2                   Running         Running 16 seconds ago

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11


[root@node2 ~]# docker service ps mynginxtest
ID             NAME            IMAGE          NODE                    DESIRED STATE   CURRENT STATE           ERROR     PORTS
fultv05jwsbm   mynginxtest.1   nginx:latest   localhost.localdomain   Running         Running 7 minutes ago             
yikbwlzinhd5   mynginxtest.2   nginx:latest   node3                   Running         Running 7 minutes ago             
f5cljf1f6d73   mynginxtest.3   nginx:latest   node2                   Running         Running 7 minutes ago             
[root@node2 ~]# docker node ls
ID                            HOSTNAME                STATUS    AVAILABILITY   MANAGER STATUS   ENGINE VERSION
jb30cv8ej8xjokjc1cu5l8kjo     localhost.localdomain   Ready     Active         Reachable        20.10.5
a5gz7qpsgbjolzgzg1tlaj8lh *   node2                   Ready     Active         Reachable        20.10.5
nmhr2t2b5cgy4l64bcwl0mxjt     node3                   Ready     Active         Leader           20.10.5
6ne9u5knznm8ei0c5uz7znka9     node4                   Ready     Active                          20.10.5

问题依旧存在(只有node3不能访问)，不搞了，等后续，欢迎留言？？？

问题最终还是解决了？？？

1
2
3
4


#以为node3的防火墙没有关，或者是leader节点不能访问？
systemctl stop docker   #让他重新选举leader，发现还是可以访问leader，
systemctl status firewalld.service    #防火墙状态关闭
systemctl start docker    #重新启动又好了,玄学

副本服务与全局服务

1
2


docker service create --mode replicated --name mytom tomcat:7  #默认worker节点创建服务
docker service create --mode global --name mytom tomcat:7      #全局

减少副本：

1

docker service update --replicas 1 mynginx

扩缩容：

1
2


docker service scale mynginxtest=5
docker service update --replicas 5 mynginxtest

1
2
3
4
5
6


ID             NAME            IMAGE          NODE                    DESIRED STATE   CURRENT STATE                ERROR     PORTS
fultv05jwsbm   mynginxtest.1   nginx:latest   localhost.localdomain   Running         Running 12 minutes ago                 
yikbwlzinhd5   mynginxtest.2   nginx:latest   node3                   Running         Running 12 minutes ago                 
f5cljf1f6d73   mynginxtest.3   nginx:latest   node2                   Running         Running 12 minutes ago          
l4blkh6mq996   mynginxtest.4   nginx:latest   node4                   Running         Running about a minute             
kvn9nhtwymds   mynginxtest.5   nginx:latest   node4                   Running         Running about a minute 

总结

swarm:

集群的管理和编排，docker可以初始化一个swarm集群，其他节点可以加入（manager OR worker）

node：

就是一个docker节点，多个节点就组成了一个网络集群

service

就是一个任务，可以在管理节点或者工作节点运行，核心

swarm网络：overlay,ingress

Docker Stack

docker-compose:适合单机部署项目！

docker stack：集群部署项目(已经快被k8s替代了)

1
2
3
4


#单机部署
docker-compose up -d wordpress.yml
#集群部署
docker stack deploy wordpress.yml

Docker Secret

安全，密码、证书配置：

Docker Config

配置：