1️⃣什么是Docker Swarm？

Docker Swarm 是什么？

Docker Swarm 是 Docker 的集群管理工具。其主要作用是把若干台 Docker 主机抽象为一个整体，并且通过一个入口统一管理这些 Docker 主机上的各种 Docker 资源。Docker Swarm 将一个或多个 Docker 节点组织起来，使得用户能够以集群方式管理它们。

Docker Swarm 组成部分

swarm 集群由管理节点（Manager）和工作节点（Worker）构成。

管理节点：主要负责整个集群的管理工作包括集群配置、服务管理等所有跟集群有关的工作。诸如监控集群状态、分发任务至工作节点等操作。

工作节点：主要负责执行运行服务的任务。

2️⃣Docker Swarm相关命令说明

🧲docker swarm |Docker 文档

# 查看docker swarm有哪些命令
[root@docker01 ~]# docker swarm
Usage:  docker swarm COMMAND
Manage Swarm
Commands:
  ca          Display and rotate the root CA
  init        Initialize a swarm
  join        Join a swarm as a node and/or manager
  join-token  Manage join tokens
  leave       Leave the swarm
  unlock      Unlock swarm
  unlock-key  Manage the unlock key
  update      Update the swarm
Run 'docker swarm COMMAND --help' for more information on a command.
# 查看docker swarm init初始化集群命令的具体操作
[root@docker01 ~]# docker swarm init --help
Usage:  docker swarm init [OPTIONS]
Initialize a swarm
Options:
      --advertise-addr string                  Advertised address (format: <ip|interface>[:port])
      --autolock                               Enable manager autolocking (requiring an unlock key to start a stopped manager)
      --availability string                    Availability of the node ("active"|"pause"|"drain") (default "active")
      --cert-expiry duration                   Validity period for node certificates (ns|us|ms|s|m|h) (default 2160h0m0s)
      --data-path-addr string                  Address or interface to use for data path traffic (format: <ip|interface>)
      --data-path-port uint32                  Port number to use for data path traffic (1024 - 49151). If no value is set or is set to 0, the default port (4789) is used.
      --default-addr-pool ipNetSlice           default address pool in CIDR format (default [])
      --default-addr-pool-mask-length uint32   default address pool subnet mask length (default 24)
      --dispatcher-heartbeat duration          Dispatcher heartbeat period (ns|us|ms|s|m|h) (default 5s)
      --external-ca external-ca                Specifications of one or more certificate signing endpoints
      --force-new-cluster                      Force create a new cluster from current state
      --listen-addr node-addr                  Listen address (format: <ip|interface>[:port]) (default 0.0.0.0:2377)
      --max-snapshots uint                     Number of additional Raft snapshots to retain
      --snapshot-interval uint                 Number of log entries between Raft snapshots (default 10000)
      --task-history-limit int                 Task history retention limit (default 5)

3️⃣Docker Swarm集群节点规划

为了利用 swarm 模式的容错功能，可以根据组织的高可用性要求实现奇数个节点。

当有多个管理中心时，可以从一个管理中心节点的故障中恢复，而无需停机。

三个管理器群可以容忍最多损失一个管理器。

五个管理器群最多可以同时丢失两个管理器节点。

七个管理器群最多可以同时丢失三个管理器节点。

九个管理器群最多可以同时丢失四个管理器节点。

Docker 建议一个群最多有七个管理器节点。

（添加更多管理器并不意味着可伸缩性或性能的提高。一般来说，情况恰恰相反。）

主机名	IP地址	docker版本号	角色	备注
manager01	192.168.200.81	20.10.14	管理节点	主管
manager02	192.168.200.82	20.10.14	管理节点	从管
manager03	192.168.200.83	20.10.14	管理节点	从管

worker01	192.168.200.91	20.10.14	工作节点	工作
worker02	192.168.200.92	20.10.14	工作节点	工作

4️⃣创建Docker Swarm高可用集群操作步骤演示

两步走操作

① 生成主节点init

② 加入（manager、worker）节点

📃 环境准备

1、修改主机名

2、配置IP地址

3、关闭防火墙和SELINUX安全模式

4、配置系统YUM源和Docker镜像源

5、更新系统（yum update -y）

6、安装好docker环境

# 查看docker版本号
[root@docker-m1 ~]# docker -v
Docker version 20.10.14, build a224086
# docker环境安装好，默认的网络信息。
[root@docker ~]# docker network ls
NETWORK ID     NAME      DRIVER    SCOPE
a656864d027c   bridge    bridge    local
9fd62dbfb07f   host      host      local
27700772b8f7   none      null      local

🎦 创建集群

$ docker swarm init --advertise-addr

🍎 docker-m1配置信息（manager）

# 创建新的群,生成主节点，执行如下命令，将工作节点添加到集群中。
[root@docker-m1 ~]# docker swarm init --advertise-addr 192.168.200.81
Swarm initialized: current node (34cug51p9dw83u2np594z6ej4) is now a manager.
To add a worker to this swarm, run the following command:
    docker swarm join --token SWMTKN-1-528o8bfk061miheduvuvnnohhpystvxnwiqfqqf04gou6n1wmz-3ixu6we70ghk69wghfrmo0y6a 192.168.200.81:2377
To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.
[root@docker-m1 ~]#
# 执行以下命令，生成如下命令，运行此命令，添加新的管理节点到集群中。
[root@docker-m1 ~]# docker swarm join-token manager
To add a manager to this swarm, run the following command:
    docker swarm join --token SWMTKN-1-528o8bfk061miheduvuvnnohhpystvxnwiqfqqf04gou6n1wmz-1z6k8msio37as0vaa467glefx 192.168.200.81:2377
[root@docker-m1 ~]#

docker-m2配置信息（manager）

# 添加至集群中成为管理节点
[root@docker-m2 ~]# docker swarm join --token SWMTKN-1-528o8bfk061miheduvuvnnohhpystvxnwiqfqqf04gou6n1wmz-1z6k8msio37as0vaa467glefx 192.168.200.81:2377
This node joined a swarm as a manager.

docker-m3配置信息（manager）

# 添加至集群中成为管理节点
[root@docker-m3 ~]# docker swarm join --token SWMTKN-1-528o8bfk061miheduvuvnnohhpystvxnwiqfqqf04gou6n1wmz-1z6k8msio37as0vaa467glefx 192.168.200.81:2377
This node joined a swarm as a manager.

🍌 docker-n1配置信息（worker）

# 添加至集群中成为工作节点
[root@docker-n1 ~]# docker swarm join --token SWMTKN-1-528o8bfk061miheduvuvnnohhpystvxnwiqfqqf04gou6n1wmz-3ixu6we70ghk69wghfrmo0y6a 192.168.200.81:2377
This node joined a swarm as a worker.

docker-n1配置信息（worker）

# 添加至集群中成为工作节点
[root@docker-n2 ~]# docker swarm join --token SWMTKN-1-528o8bfk061miheduvuvnnohhpystvxnwiqfqqf04gou6n1wmz-3ixu6we70ghk69wghfrmo0y6a 192.168.200.81:2377
This node joined a swarm as a worker.

🔨检查配置情况

查看集群节点状态信息

发现docker-m1是主管理节点，docker-m2、docker-03是备用管理节点；

两个工作节点docker-n1、docker-n2也正常添加至集群中来。

[root@docker-m1 ~]# docker node ls
ID                            HOSTNAME    STATUS    AVAILABILITY   MANAGER STATUS   ENGINE VERSION
34cug51p9dw83u2np594z6ej4 *   docker-m1   Ready     Active         Leader           20.10.14
hwmwdk78u3rx0wwxged87xnun     docker-m2   Ready     Active         Reachable        20.10.14
4q34guc6hp2a5ok0g1zkjojyh     docker-m3   Ready     Active         Reachable        20.10.14
4om9sg56sg09t9whelbrkh8qn     docker-n1   Ready     Active                          20.10.14
xooolkg0g9epddfqqiicywshe     docker-n2   Ready     Active                          20.10.14
[root@docker-m1 ~]#

查看整个Docker系统的信息

发现docker swarm集群已经创建完成。

共有五台节点，其中三台为管理节点。

[root@docker-m1 ~]# docker info
Client:
 Context:    default
 Debug Mode: false
 Plugins:
  app: Docker App (Docker Inc., v0.9.1-beta3)
  buildx: Docker Buildx (Docker Inc., v0.8.1-docker)
  scan: Docker Scan (Docker Inc., v0.17.0)
Server:
 Containers: 0
  Running: 0
  Paused: 0
  Stopped: 0
 Images: 0
 Server Version: 20.10.14
 Storage Driver: overlay2
  Backing Filesystem: xfs
  Supports d_type: true
  Native Overlay Diff: true
  userxattr: false
 Logging Driver: json-file
 Cgroup Driver: systemd
 Cgroup Version: 1
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local logentries splunk syslog
 Swarm: active
  NodeID: 34cug51p9dw83u2np594z6ej4
  Is Manager: true
  ClusterID: v1r77dlrbucscss3tss6edpfv
  Managers: 3
  Nodes: 5
  Default Address Pool: 10.0.0.0/8
  SubnetSize: 24
  Data Path Port: 4789
  Orchestration:
   Task History Retention Limit: 5
  Raft:
   Snapshot Interval: 10000
   Number of Old Snapshots to Retain: 0
   Heartbeat Tick: 1
   Election Tick: 10
  Dispatcher:
   Heartbeat Period: 5 seconds
  CA Configuration:
   Expiry Duration: 3 months
   Force Rotate: 0
  Autolock Managers: false
  Root Rotation In Progress: false
  Node Address: 192.168.200.81
  Manager Addresses:
   192.168.200.81:2377
   192.168.200.82:2377
   192.168.200.83:2377
 Runtimes: io.containerd.runc.v2 io.containerd.runtime.v1.linux runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 3df54a852345ae127d1fa3092b95168e4a88e2f8
 runc version: v1.0.3-0-gf46b6ba
 init version: de40ad0
 Security Options:
  seccomp
   Profile: default
 Kernel Version: 3.10.0-1160.62.1.el7.x86_64
 Operating System: CentOS Linux 7 (Core)
 OSType: linux
 Architecture: x86_64
 CPUs: 1
 Total Memory: 1.934GiB
 Name: docker-m1
 ID: YIQB:NBLI:MUUN:35IY:ESCK:QPI3:CIZP:U2AS:WV7D:E57G:H7CO:WBWI
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 Registry: https://index.docker.io/v1/
 Labels:
 Experimental: false
 Insecure Registries:
  127.0.0.0/8
 Registry Mirrors:
  https://w2kavmmf.mirror.aliyuncs.com/
 Live Restore Enabled: false
WARNING: IPv4 forwarding is disabled
WARNING: bridge-nf-call-iptables is disabled
WARNING: bridge-nf-call-ip6tables is disabled
[root@docker-m1 ~]#

查询集群网络信息

查看到集群中各个节点的IP地址

[root@docker-m1 ~]# docker network ls
NETWORK ID     NAME              DRIVER    SCOPE
a656864d027c   bridge            bridge    local
1359459aa236   docker_gwbridge   bridge    local
9fd62dbfb07f   host              host      local
6ipkh8htdyiv   ingress           overlay   swarm
27700772b8f7   none              null      local
[root@docker-m1 ~]# docker network inspect 6ipkh8htdyiv
[
    {
        "Name": "ingress",
        "Id": "6ipkh8htdyivqfqwcdcehu8mb",
        "Created": "2022-05-03T18:51:39.108622642+08:00",
        "Scope": "swarm",
        "Driver": "overlay",
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": null,
            "Config": [
                {
                    "Subnet": "10.0.0.0/24",
                    "Gateway": "10.0.0.1"
                }
            ]
        },
        "Internal": false,
        "Attachable": false,
        "Ingress": true,
        "ConfigFrom": {
            "Network": ""
        },
        "ConfigOnly": false,
        "Containers": {
            "ingress-sbox": {
                "Name": "ingress-endpoint",
                "EndpointID": "aaa7e77674405f75c1ef8ecf563a5e1745778e9fa698863a243d32121c58dcc5",
                "MacAddress": "02:42:0a:00:00:02",
                "IPv4Address": "10.0.0.2/24",
                "IPv6Address": ""
            }
        },
        "Options": {
            "com.docker.network.driver.overlay.vxlanid_list": "4096"
        },
        "Labels": {},
        "Peers": [
            {
                "Name": "052c54656ba2",
                "IP": "192.168.200.81"
            },
            {
                "Name": "e9e6959ea728",
                "IP": "192.168.200.82"
            },
            {
                "Name": "08a7107b1250",
                "IP": "192.168.200.83"
            },
            {
                "Name": "b0e6bcd74c9f",
                "IP": "192.168.200.91"
            },
            {
                "Name": "0d537d72fb87",
                "IP": "192.168.200.92"
            }
        ]
    }
]
[root@docker-m1 ~]#

5️⃣更改角色：将Manager降级为Worker

以docker-m3为例，将docker-m3管理节点由manager角色变成worker角色。

# 查看帮助命令
[root@docker-m1 ~]# docker node update -h
Flag shorthand -h has been deprecated, please use --help
Usage:  docker node update [OPTIONS] NODE
Update a node
Options:
      --availability string   Availability of the node ("active"|"pause"|"drain")
      --label-add list        Add or update a node label (key=value)
      --label-rm list         Remove a node label if exists
      --role string           Role of the node ("worker"|"manager")
# 执行如下命令，将docker-m3管理节点由manager角色变成worker角色。
[root@docker-m1 ~]# docker node ls
ID                            HOSTNAME    STATUS    AVAILABILITY   MANAGER STATUS   ENGINE VERSION
34cug51p9dw83u2np594z6ej4 *   docker-m1   Ready     Active         Leader           20.10.14
hwmwdk78u3rx0wwxged87xnun     docker-m2   Ready     Active         Reachable        20.10.14
4q34guc6hp2a5ok0g1zkjojyh     docker-m3   Ready     Active         Reachable        20.10.14
4om9sg56sg09t9whelbrkh8qn     docker-n1   Ready     Active                          20.10.14
xooolkg0g9epddfqqiicywshe     docker-n2   Ready     Active                          20.10.14
[root@docker-m1 ~]# docker node update --role worker docker-m3
docker-m3
[root@docker-m1 ~]# docker node ls
ID                            HOSTNAME    STATUS    AVAILABILITY   MANAGER STATUS   ENGINE VERSION
34cug51p9dw83u2np594z6ej4 *   docker-m1   Ready     Active         Leader           20.10.14
hwmwdk78u3rx0wwxged87xnun     docker-m2   Ready     Active         Reachable        20.10.14
4q34guc6hp2a5ok0g1zkjojyh     docker-m3   Ready     Active                          20.10.14
4om9sg56sg09t9whelbrkh8qn     docker-n1   Ready     Active                          20.10.14
xooolkg0g9epddfqqiicywshe     docker-n2   Ready     Active                          20.10.14
[root@docker-m1 ~]#

# 更改之后，查看docker-m3节点详细信息情况
# 发现已经由管理节点变成工作节点
[root@docker-m1 ~]# docker node inspect 4q34guc6hp2a5ok0g1zkjojyh
[
    {
        "ID": "4q34guc6hp2a5ok0g1zkjojyh",
        "Version": {
            "Index": 39
        },
        "CreatedAt": "2022-05-03T10:59:07.69499678Z",
        "UpdatedAt": "2022-05-03T11:27:02.178601504Z",
        "Spec": {
            "Labels": {},
            "Role": "worker",
            "Availability": "active"
        },
        "Description": {
            "Hostname": "docker-m3",
            "Platform": {
                "Architecture": "x86_64",
                "OS": "linux"
            },
            "Resources": {
                "NanoCPUs": 1000000000,
                "MemoryBytes": 2076499968
            },
            "Engine": {
                "EngineVersion": "20.10.14",
                "Plugins": [
                    {
                        "Type": "Log",
                        "Name": "awslogs"
                    },
                    {
                        "Type": "Log",
                        "Name": "fluentd"
                    },
                    {
                        "Type": "Log",
                        "Name": "gcplogs"
                    },
                    {
                        "Type": "Log",
                        "Name": "gelf"
                    },
                    {
                        "Type": "Log",
                        "Name": "journald"
                    },
                    {
                        "Type": "Log",
                        "Name": "json-file"
                    },
                    {
                        "Type": "Log",
                        "Name": "local"
                    },
                    {
                        "Type": "Log",
                        "Name": "logentries"
                    },
                    {
                        "Type": "Log",
                        "Name": "splunk"
                    },
                    {
                        "Type": "Log",
                        "Name": "syslog"
                    },
                    {
                        "Type": "Network",
                        "Name": "bridge"
                    },
                    {
                        "Type": "Network",
                        "Name": "host"
                    },
                    {
                        "Type": "Network",
                        "Name": "ipvlan"
                    },
                    {
                        "Type": "Network",
                        "Name": "macvlan"
                    },
                    {
                        "Type": "Network",
                        "Name": "null"
                    },
                    {
                        "Type": "Network",
                        "Name": "overlay"
                    },
                    {
                        "Type": "Volume",
                        "Name": "local"
                    }
                ]
            },
            "TLSInfo": {
                "TrustRoot": "-----BEGIN CERTIFICATE-----\nMIIBaTCCARCgAwIBAgIUYUzIe4mqhjKYxuilbhVByLwzzeMwCgYIKoZIzj0EAwIw\nEzERMA8GA1UEAxMIc3dhcm0tY2EwHhcNMjIwNTAzMTA0NzAwWhcNNDIwNDI4MTA0\nNzAwWjATMREwDwYDVQQDEwhzd2FybS1jYTBZMBMGByqGSM49AgEGCCqGSM49AwEH\nA0IABK8XzVHRM50TgsAxrgXg18ti69dkedf9LsaHm2I2ub9kKzkLsnTV+bIHGOHK\n0/Twi/B9OCFSsozUGDP7qR3/rRmjQjBAMA4GA1UdDwEB/wQEAwIBBjAPBgNVHRMB\nAf8EBTADAQH/MB0GA1UdDgQWBBQ3iXSq5FKnODK2Qqic39A0bg9qjjAKBggqhkjO\nPQQDAgNHADBEAiASv1HdziErIzBJtsVMxfp8zAv0EJ5/eVeIldYdUIVNTQIgXUc3\nakty/iBy5/MhFt9JRRMV1xH1x+Dcf35tNWGH52w=\n-----END CERTIFICATE-----\n",
                "CertIssuerSubject": "MBMxETAPBgNVBAMTCHN3YXJtLWNh",
                "CertIssuerPublicKey": "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAErxfNUdEznROCwDGuBeDXy2Lr12R51/0uxoebYja5v2QrOQuydNX5sgcY4crT9PCL8H04IVKyjNQYM/upHf+tGQ=="
            }
        },
        "Status": {
            "State": "ready",
            "Addr": "192.168.200.83"
        }
    }
]
[root@docker-m1 ~]#

【Docker Swarm】搭建Docker Swarm高可用集群（详细版）（上）

1️⃣什么是Docker Swarm？

2️⃣Docker Swarm相关命令说明

3️⃣Docker Swarm集群节点规划

4️⃣创建Docker Swarm高可用集群操作步骤演示

📃 环境准备

🎦 创建集群

🍎 docker-m1配置信息（manager）

docker-m2配置信息（manager）

docker-m3配置信息（manager）

🍌 docker-n1配置信息（worker）

docker-n1配置信息（worker）

🔨检查配置情况

5️⃣更改角色：将Manager降级为Worker

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