ETCD
是一個分佈式一致性k-v存儲系統,可用於服務註冊發現與共享配置。具備一下優勢:node
容器在兩個跨主機通訊的時候,是使用overlay network這個網絡模式進行通訊,若是使用host也能夠實現跨主機進行通訊,直接使用這個物理的ip地址就能夠進行通訊。overlay它會虛擬出一個網絡好比10.0.9.3 這個ip地址,在這個overlay網絡模式裏面,有一個相似於服務網關的地址,而後這個包轉發到物理服務器這個地址,最終經過路由和交換,到達另外一個服務器的ip地址。linux
在docker容器裏面overlay是怎麼實現的呢?git
咱們會有一個服務發現,好比說consul,會定義一個ip地址池,好比10.0.9.0/24 之類的,上面會有容器,容器ip地址會從上面去獲取,獲取完了後,會經過eth1進行通訊,賊這實現跨主機的東西。github
node1部署算法
[root@node1 ~]# wget https://github.com/coreos/etcd/releases/download/v3.0.12/etcd-v3.0.12-linux-amd64.tar.gz [root@node1 ~]# tar zxf etcd-v3.0.12-linux-amd64.tar.gz [root@node1 ~]# cd etcd-v3.0.12-linux-amd64/ [root@node1 etcd-v3.0.12-linux-amd64]# nohup ./etcd --name docker-node1 --initial-advertise-peer-urls http://10.211.55.12:2380 \ > --listen-peer-urls http://10.211.55.12:2380 \ > --listen-client-urls http://10.211.55.12:2379,http://127.0.0.1:2379 \ > --advertise-client-urls http://10.211.55.12:2379 \ > --initial-cluster-token etcd-cluster \ > --initial-cluster docker-node1=http://10.211.55.12:2380,docker-node2=http://10.211.55.13:2380 \ > --initial-cluster-state new& [1] 32505
node2部署docker
[root@node2 ~]# wget https://github.com/coreos/etcd/releases/download/v3.0.12/etcd-v3.0.12-linux-amd64.tar.gz [root@node2 ~]# tar zxf etcd-v3.0.12-linux-amd64.tar.gz [root@node2 ~]# cd etcd-v3.0.12-linux-amd64/ [root@node2 etcd-v3.0.12-linux-amd64]# nohup ./etcd --name docker-node2 --initial-advertise-peer-urls http://10.211.55.13:2380 \ > --listen-peer-urls http://10.211.55.13:2380 \ > --listen-client-urls http://10.211.55.13:2379,http://127.0.0.1:2379 \ > --advertise-client-urls http://10.211.55.13:2379 \ > --initial-cluster-token etcd-cluster \ > --initial-cluster docker-node1=http://10.211.55.12:2380,docker-node2=http://10.211.55.13:2380 \ > --initial-cluster-state new& [1] 19240
檢查cluster狀態vim
[root@node2 etcd-v3.0.12-linux-amd64]# ./etcdctl cluster-health member 98da03f1eca9d9d is healthy: got healthy result from http://10.211.55.12:2379 member 63a987e985acb514 is healthy: got healthy result from http://10.211.55.13:2379 cluster is healthy
參數說明安全
參數說明: ● –data-dir 指定節點的數據存儲目錄,若不指定,則默認是當前目錄。這些數據包括節點ID,集羣ID,集羣初始化配置,Snapshot文件,若未指 定–wal-dir,還會存儲WAL文件 ● –wal-dir 指定節點的was文件存儲目錄,若指定了該參數,wal文件會和其餘數據文件分開存儲 ● –name 節點名稱 ● –initial-advertise-peer-urls 告知集羣其餘節點的URL,tcp2380端口用於集羣通訊 ● –listen-peer-urls 監聽URL,用於與其餘節點通信 ● –advertise-client-urls 告知客戶端的URL, 也就是服務的URL,tcp2379端口用於監聽客戶端請求 ● –initial-cluster-token 集羣的ID ● –initial-cluster 集羣中全部節點 ● –initial-cluster-state 集羣狀態,new爲新建立集羣,existing爲已存在的集羣
1.查看集羣版本 # etcdctl --version # etcdctl --help 1 2 2.查看集羣健康狀態 # etcdctl cluster-health 1 3.查看集羣成員 # etcdctl member list 1 在任一節點上執行,能夠看到集羣的節點狀況,並能看出哪一個是leader節點 4.更新一個節點 若是你想更新一個節點的IP(peerURLS),首先你須要知道那個節點的ID # etcdctl member list # etcdctl member update memberID http://ip:2380 1 2 5.刪除一個節點(Etcd集羣成員的縮) # etcdctl member list # etcdctl member remove memberID # etcdctl member list # ps -ef|grep etcd //在相關節點上kill掉etcd進程 1 2 3 4 6.增長一個新節點(Etcd集羣成員的伸) 注意:步驟很重要,否則會報集羣ID不匹配 # etcdctl member add --help 1 a. 將目標節點添加到集羣 # etcdctl member add etcd3 http://10.1.2.174:2380 Addedmember named etcd3 with ID 28e0d98e7ec15cd4 to cluster ETCD_NAME="etcd3" ETCD_INITIAL_CLUSTER="etcd0=http://10.1.2.61:2380,etcd1=http://10.1.2.172:2380,etcd2=http://10.1.2.173:2380,etcd3=http://10.1.2.174:2380" ETCD_INITIAL_CLUSTER_STATE="existing" 1 2 3 4 5 6 b. 查看新增成員列表,etcd3狀態爲unstarted # etcdctl member list d4f257d2b5f99b64[unstarted]:peerURLs=http://10.1.2.174:2380 1 2 c. 清空目標節點etcd3的data-dir 節點刪除後,集羣中的成員信息會更新,新節點是做爲一個全新的節點加入集羣,若是data-dir有數據,etcd啓動時會讀取己經存在的數據,仍然用老的memberID會形成沒法加入集羣,因此必定要清空新節點的data-dir。 # rm -rf /path/to/etcd/data 1 d. 在目標節點上啓動新增長的成員 這裏的initial標記必定要指定爲existing,若是爲new,則會自動生成一個新的memberID,這和前面添加節點時生成的ID不一致,故日誌中會報節點ID不匹配的錯。 # vim etcd3.sh 1 修改etcd3.sh,腳本中–advertise-client-urls 和 –initial-advertis-peer-urls 參數修改成etcd3的,–initial-cluster-state改成existing # nohup ./etcd3.sh & # etcdctl member list
node1服務器
[root@node1 ~]#service docker stop [root@node1 ~]# /usr/bin/dockerd -H tcp://0.0.0.0:2375 -H unix:///var/run/docker.sock --cluster-store=etcd://10.211.55.12:2379 --cluster-advertise=10.211.55.12:2375&
node2網絡
[root@node2 ~]#service docker stop [root@node2 ~]# /usr/bin/dockerd -H tcp://0.0.0.0:2375 -H unix:///var/run/docker.sock --cluster-store=etcd://10.211.55.13:2379 --cluster-advertise=10.211.55.13:2375&
在node1上建立一個demo的overlay network
[root@node1 ~]# docker network ls NETWORK ID NAME DRIVER SCOPE 550d5b450fe3 bridge bridge local cca92be73cc6 host host local d21360748bfc none null local [root@node1 ~]# docker network create -d overlay demo 97e959031044ec634d61d2e721cb0348d7ff852af3f575d75d2988c07e0f9846 [root@node1 ~]# docker network ls NETWORK ID NAME DRIVER SCOPE 550d5b450fe3 bridge bridge local 97e959031044 demo overlay global cca92be73cc6 host host local d21360748bfc none null local [root@node1 ~]# docker network inspect demo [ { "Name": "demo", "Id": "97e959031044ec634d61d2e721cb0348d7ff852af3f575d75d2988c07e0f9846", "Created": "2018-08-01T22:22:01.958142468+08:00", "Scope": "global", "Driver": "overlay", "EnableIPv6": false, "IPAM": { "Driver": "default", "Options": {}, "Config": [ { "Subnet": "10.0.0.0/24", "Gateway": "10.0.0.1" } ] }, "Internal": false, "Attachable": false, "Ingress": false, "ConfigFrom": { "Network": "" }, "ConfigOnly": false, "Containers": {}, "Options": {}, "Labels": {} } ]
咱們會看到在node2上,這個demo的overlay network會被同步建立
[root@node2 etcd-v3.0.12-linux-amd64]# cd [root@node2 ~]# docker network ls NETWORK ID NAME DRIVER SCOPE c6af37ef6765 bridge bridge local 97e959031044 demo overlay global de15cdab46b0 host host local cc3ec612fd29 none null local # 說明etcd分佈式存儲已經起做用,兩個節點數據已同步
經過查看etcd的key-value, 咱們獲取到,這個demo的network是經過etcd從node1同步到node2的
[root@node2 etcd-v3.0.12-linux-amd64]# ./etcdctl ls /docker /docker/nodes /docker/network [root@node2 etcd-v3.0.12-linux-amd64]# ./etcdctl ls /docker/nodes /docker/nodes/10.211.55.12:2375 /docker/nodes/10.211.55.13:2375 [root@node2 etcd-v3.0.12-linux-amd64]# ./etcdctl ls /docker/network/v1.0/network /docker/network/v1.0/network/97e959031044ec634d61d2e721cb0348d7ff852af3f575d75d2988c07e0f9846 [root@node2 etcd-v3.0.12-linux-amd64]# ./etcdctl get /docker/network/v1.0/network/97e959031044ec634d61d2e721cb0348d7ff852af3f575d75d2988c07e0f9846 {"addrSpace":"GlobalDefault","attachable":false,"configFrom":"","configOnly":false,"created":"2018-08-01T22:22:01.958142468+08:00","enableIPv6":false,"generic":{"com.docker.network.enable_ipv6":false,"com.docker.network.generic":{}},"id":"97e959031044ec634d61d2e721cb0348d7ff852af3f575d75d2988c07e0f9846","inDelete":false,"ingress":false,"internal":false,"ipamOptions":{},"ipamType":"default","ipamV4Config":"[{\"PreferredPool\":\"\",\"SubPool\":\"\",\"Gateway\":\"\",\"AuxAddresses\":null}]","ipamV4Info":"[{\"IPAMData\":\"{\\\"AddressSpace\\\":\\\"GlobalDefault\\\",\\\"Gateway\\\":\\\"10.0.0.1/24\\\",\\\"Pool\\\":\\\"10.0.0.0/24\\\"}\",\"PoolID\":\"GlobalDefault/10.0.0.0/24\"}]","labels":{},"loadBalancerIP":"","name":"demo","networkType":"overlay","persist":true,"postIPv6":false,"scope":"global"}
node1
[root@node1 ~]# docker run -d --name test1 --net demo busybox sh -c "while true; do sleep 3600; done" Unable to find image 'busybox:latest' locally latest: Pulling from library/busybox 8c5a7da1afbc: Pull complete Digest: sha256:cb63aa0641a885f54de20f61d152187419e8f6b159ed11a251a09d115fdff9bd Status: Downloaded newer image for busybox:latest 4bc3ab1cb7d838e8ef314618e6d3d878e744ef7842196a00b3999e6b6fe8402f ERRO[2018-08-01T22:26:33.105124642+08:00] Failed to deserialize netlink ndmsg: invalid argument INFO[0379] shim docker-containerd-shim started address="/containerd-shim/moby/4bc3ab1cb7d838e8ef314618e6d3d878e744ef7842196a00b3999e6b6fe8402f/shim.sock" debug=false pid=6630 [root@node1 ~]# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 4bc3ab1cb7d8 busybox "sh -c 'while true; …" 26 seconds ago Up 24 seconds test1 [root@node1 ~]# docker exec test1 ifconfig eth0 Link encap:Ethernet HWaddr 02:42:0A:00:00:02 inet addr:10.0.0.2 Bcast:10.0.0.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1450 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) eth1 Link encap:Ethernet HWaddr 02:42:AC:12:00:02 inet addr:172.18.0.2 Bcast:172.18.255.255 Mask:255.255.0.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:31 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:4045 (3.9 KiB) TX bytes:0 (0.0 B) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
node2
[root@node2 ~]# docker run -d --name test1 --net demo busybox sh -c "while true; do sleep 3600; done" Unable to find image 'busybox:latest' locally latest: Pulling from library/busybox 56bec22e3559: Pull complete Digest: sha256:29f5d56d12684887bdfa50dcd29fc31eea4aaf4ad3bec43daf19026a7ce69912 Status: Downloaded newer image for busybox:latest fad6dc6538a85d3dcc958e8ed7b1ec3810feee3e454c1d3f4e53ba25429b290b docker: Error response from daemon: service endpoint with name test1 already exists. # 容器已存在 [root@node2 ~]# docker run -d --name test2 --net demo busybox sh -c "while true; do sleep 3600; done" 9d494a2f66a69e6b861961d0c6af2446265bec9b1d273d7e70d0e46eb2e98d20
驗證連通性
[root@node2 etcd-v3.0.12-linux-amd64]# docker exec -it test2 ifconfig eth0 Link encap:Ethernet HWaddr 02:42:0A:00:00:03 inet addr:10.0.0.3 Bcast:10.0.0.255 Mask:255.255.255.0 UP BROADCAST RUNNING MULTICAST MTU:1450 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) eth1 Link encap:Ethernet HWaddr 02:42:AC:12:00:02 inet addr:172.18.0.2 Bcast:172.18.255.255 Mask:255.255.0.0 UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:32 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:4110 (4.0 KiB) TX bytes:0 (0.0 B) lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) [root@node1 ~]# docker exec test1 sh -c "ping 10.0.0.3" PING 10.0.0.3 (10.0.0.3): 56 data bytes 64 bytes from 10.0.0.3: seq=0 ttl=64 time=0.698 ms 64 bytes from 10.0.0.3: seq=1 ttl=64 time=1.034 ms 64 bytes from 10.0.0.3: seq=2 ttl=64 time=1.177 ms 64 bytes from 10.0.0.3: seq=3 ttl=64 time=0.708 ms 64 bytes from 10.0.0.3: seq=4 ttl=64 time=0.651 ms