Docker Swarm 叢集部署
介紹
Swarm 作為Docker 三劍客之一，於2014年提出，自 v1.12.3 以來， docker swarm 成為 docker 引擎內建的服務。它和谷歌的 K8s 產生了直接競爭。很難說哪個好，對於熟悉 docker 容器的人來說，docker swarm 應該友好一些。
安裝
準備材料:
1、硬體：centos 7 2臺(可以是虛擬機器)
2、docker 版本: 172.16.0.45 是 18.06.0-ce
172.16.0.43 是 1.13.1
3、yum 源 ：阿里源
部署叢集:
1、在master上執行docker pull swarm 拉取swarm映象
2、初始化swarm : docker swarm init --advertise-addr 172.16.0.45
[[email protected] /]# docker swarm init --advertise-addr 172.16.0.45 Swarm initialized: current node (npb3iydf14kkts0b5ie66k2vn) is now a manager. To add a worker to this swarm, run the following command: docker swarm join --token SWMTKN-1-4j7abdlcx8seeia13e609hy536gu0vazt3gz1tv7nao0072wwl-3igsdtz5niaoxvt6ysmskt031 172.16.0.45:2377 To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.
注: docker swarm join --token SWMTKN-1-4j7abdlcx8seeia13e609hy536gu0vazt3gz1tv7nao0072wwl-3igsdtz5niaoxvt6ysmskt031 172.16.0.45:2377 為加入該叢集的服務需要執行的tokenId
3、在node 上執行docker pull swarm 拉取swarm映象
[[email protected]_hdp_03 home]# docker pull swarm Using default tag: latest Trying to pull repository docker.io/library/swarm ... sha256:406022f04a3d0c5ce4dbdb60422f24052c20ab7e6d41ebe5723aa649c3833975: Pulling from docker.io/library/swarm d85c18077b82: Pull complete 1e6bb16f8cb1: Pull complete 85bac13497d7: Pull complete Digest: sha256:406022f04a3d0c5ce4dbdb60422f24052c20ab7e6d41ebe5723aa649c3833975 Status: Downloaded newer image for docker.io/swarm:latest
4、在node 上執行 docker swarm join --token SWMTKN-1-4j7abdlcx8seeia13e609hy536gu0vazt3gz1tv7nao0072wwl-3igsdtz5niaoxvt6ysmskt031 172.16.0.45:2377 即可加入45上建立的叢集
[[email protected]_hdp_03 home]# docker swarm join --token SWMTKN-1-4j7abdlcx8seeia13e609hy536gu0vazt3gz1tv7nao0072wwl-3igsdtz5niaoxvt6ysmskt031 172.16.0.45:2377
This node joined a swarm as a worker.
5、如果返回This node joined a swarm as a worker. 標識成功加入叢集
6、如果返回Error response from daemon: rpc error: code = 14 desc = grpc: the connection is unavailable 考慮防火牆問題
7、採用firewall-cmd --state 查詢防火牆（如果返回not running 標識沒有執行）
如果要採用防火牆那麼需要通過開發下拉埠
firewall-cmd --add-port=2376/tcp --permanent
firewall-cmd --add-port=2377/tcp --permanent
firewall-cmd --add-port=7946/tcp --permanent
firewall-cmd --add-port=7946/udp --permanent
firewall-cmd --add-port=4789/udp --permanent切記需要重啟docker 才能生效。
8、在master 上執行docker node ls 來檢視叢集中的節點
[[email protected] /]# docker node ls
ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS ENGINE VERSION
npb3iydf14kkts0b5ie66k2vn * k8smaster Ready Active Leader 18.06.0-ce
qn9ewaj1kxn9g6wclylsow1vi pb_hdp_03 Ready Active 1.13.1
輸出資訊第二行 id 後面的*表示當前連線到了該節點。HOSTNAME 欄輸出節點的 hostname。MANAGER 用於指示 swarm中的管理節點，該欄值為 Leader 表示為管理節點，空值表示為工作節點
9、在master 上執行docker node ps 檢視當前節點容器資訊（類似於docker ps）
[[email protected] /]# docker node ps
ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR PORTS
tf6rgcdtg9lz helloworld.1 busybox:1.25.1-musl k8smaster Running Running about an hour ago
sx52pbyed2jg helloworld.4 busybox:1.25.1-musl k8smaster Running Running about an hour ago 測試叢集：
1、在master上通過“docker service create --replicas 1 --name helloworld busybox:1.25.1-musl /bin/sh -c "while true; do echo hello world; sleep 3; done"”來建立一個服務，每隔三秒輸出一個 “hello world”
[[email protected] /]# docker service create --replicas 1 --name helloworld busybox:1.25.1-musl /bin/sh -c "while true; do echo hello world; sleep 3; done"
edkbe2lic2ie9vl7cxbihfn0n
overall progress: 1 out of 1 tasks
1/1: running [==================================================>]
verify: Service converged
解說：
docker service create 命令建立服務。 --name 標誌將服務命名為helloworld。 --replicas 標誌指定了期望狀態為 1 個執行示例。 引數 busybox:1.25.1-musl /bin/sh -c "while true; do echo hello world; sleep 3; done 將服務定義為使用映象busybox:1.25.1-musl 建立容器，並在裡面執行 /bin/sh -c "while true; do echo hello world; sleep 3; done"。
2、在master上通過docker service ls 查詢服務列表
[[email protected] /]# docker service ls
ID NAME MODE REPLICAS IMAGE PORTS
edkbe2lic2ie helloworld replicated 1/1 busybox:1.25.1-musl
3、通過“docker service inspect --pretty helloworld” 查詢容器的詳細資訊
[[email protected] /]# docker service inspect --pretty helloworld
ID: edkbe2lic2ie9vl7cxbihfn0n
Name: helloworld
Service Mode: Replicated
Replicas: 5
Placement:
UpdateConfig:
Parallelism: 1
On failure: pause
Monitoring Period: 5s
Max failure ratio: 0
Update order: stop-first
RollbackConfig:
Parallelism: 1
On failure: pause
Monitoring Period: 5s
Max failure ratio: 0
Rollback order: stop-first
ContainerSpec:
Image: busybox:[email protected]:46634e32e559271b8e18b7f1b21d981da4cd63ed8d36fbdc35c0b56464238a0c
Args: /bin/sh -c while true; do echo hello world; sleep 3; done
Init: false
Resources:
Endpoint Mode: vip
4、檢視那個節點執行在該服務上 docker service ps helloworld
[[email protected] /]# docker service ps helloworld
ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR PORTS
tf6rgcdtg9lz helloworld.1 busybox:1.25.1-musl k8smaster Running Running 2 hours ago
pnv59taeonqy helloworld.2 busybox:1.25.1-musl pb_hdp_03 Running Running about an hour ago
qccg5si9wtxm helloworld.3 busybox:1.25.1-musl pb_hdp_03 Running Running about an hour ago
sx52pbyed2jg helloworld.4 busybox:1.25.1-musl k8smaster Running Running about an hour ago
r0riw4d2hvrt helloworld.5 busybox:1.25.1-musl pb_hdp_03 Running Running about an hour ago 5、刪除執行的服務 docker service rm helloworld
[[email protected] /]# docker service rm helloworld
helloworld
6、docker service ls 檢視執行在叢集上的服務
下線節點：
1、通過docker node ls 檢視當前活動的節點
[[email protected] /]# docker node ls
ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS ENGINE VERSION
npb3iydf14kkts0b5ie66k2vn * k8smaster Ready Active Leader 18.06.0-ce
qn9ewaj1kxn9g6wclylsow1vi pb_hdp_03 Ready Active 1.13.1
2、通過docker node update --availability drain pb_hdp_03 下線名稱為pb_hdp_03 的節點
[[email protected] /]# docker node update --availability drain pb_hdp_03
pb_hdp_03
[[email protected] /]# docker service ps helloworld
ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR PORTS
wmjzu4nrra59 helloworld.1 busybox:1.25.1-musl k8smaster Ready Ready 5 seconds ago
90zczn851j81 \_ helloworld.1 busybox:1.25.1-musl pb_hdp_03 Shutdown Running 6 seconds ago
rxzzchtmlnb5 helloworld.2 busybox:1.25.1-musl k8smaster Ready Ready 5 seconds ago
v5qlp8cma8tj \_ helloworld.2 busybox:1.25.1-musl pb_hdp_03 Shutdown Running 6 seconds ago
1nrd1op72awm helloworld.3 busybox:1.25.1-musl k8smaster Running Running 2 minutes ago
vntrn9vwumxq helloworld.4 busybox:1.25.1-musl k8smaster Ready Ready 4 seconds ago
pbxar3qcyvgf \_ helloworld.4 busybox:1.25.1-musl pb_hdp_03 Shutdown Running 6 seconds ago
j0thl91hkm53 helloworld.5 busybox:1.25.1-musl k8smaster Running Running 2 minutes ago 可以看到該節點的狀態為Ready，但可用性為Drain
3、通過docker node update --availability active pb_hdp_03 再次將pb_hdp_03啟用
[[email protected] /]# docker node update --availability active pb_hdp_03
pb_hdp_03
[[email protected] /]# docker service ps helloworld
ID NAME IMAGE NODE DESIRED STATE CURRENT STATE ERROR PORTS
wmjzu4nrra59 helloworld.1 busybox:1.25.1-musl k8smaster Running Running 2 minutes ago
90zczn851j81 \_ helloworld.1 busybox:1.25.1-musl pb_hdp_03 Shutdown Shutdown 2 minutes ago
rxzzchtmlnb5 helloworld.2 busybox:1.25.1-musl k8smaster Running Running 2 minutes ago
v5qlp8cma8tj \_ helloworld.2 busybox:1.25.1-musl pb_hdp_03 Shutdown Shutdown 2 minutes ago
1nrd1op72awm helloworld.3 busybox:1.25.1-musl k8smaster Running Running 5 minutes ago
vntrn9vwumxq helloworld.4 busybox:1.25.1-musl k8smaster Running Running 2 minutes ago
pbxar3qcyvgf \_ helloworld.4 busybox:1.25.1-musl pb_hdp_03 Shutdown Shutdown 2 minutes ago
j0thl91hkm53 helloworld.5 busybox:1.25.1-musl k8smaster Running Running 5 minutes ago 說明現在該節點又可以重新接收任務了。
注：
一個可用性為Active的節點在以下情況下可以接收到新任務：
- 當一個服務在伸縮規模時
- 滾動更新時
- 當你把其他某個節點的可用性設為
Drain時 - 當某個任務在另外某個
Active節點上啟動失敗時