Consul的安裝與試用

2016-5-23

一）安裝在RedHat7.2上

1. [email protected] info

[[email protected]]# uname -a

Linuxip-172-30-0-43.ec2.internal 3.10.0-327.el7.x86_64 #1 SMP Thu Oct 2917:29:29 EDT 2015 x86_64 x86_64 x86_64 GNU/Linux

[[email protected]]# cat /etc/redhat-release

RedHat Enterprise Linux Server release 7.2 (Maipo)

2. 安裝

主頁https://www.consul.io/

當然 版本

https://releases.hashicorp.com/consul/0.6.4/consul_0.6.4_linux_amd64.zip

下載， 然後unzip 解壓， 得到唯一個可執行檔案

wgethttps://releases.hashicorp.com/consul/0.6.4/consul_0.6.4_linux_amd64.zip

unzipconsul_0.6.4_linux_amd64.zip

檢查一下版本

[[email protected]]# ./consul version

Consulv0.6.4

ConsulProtocol: 3 (Understands back to: 1)

[[email protected]]#

3. 以Bootstrap Server 模式 啟動

./consulagent -server -bootstrap-expect=1 -data-dir /tmp/consul

./consulagent -server -bootstrap -data-dir /tmp/consul

輸出如下：

[[email protected]]# ./consul agent -server -bootstrap-expect=1 -data-dir/tmp/consul

==>WARNING: BootstrapExpect Mode is specified as 1; this is the same asBootstrap mode.

==>WARNING: Bootstrap mode enabled! Do not enable unless necessary

==>Starting Consul agent...

==>Starting Consul agent RPC...

==>Consul agent running!

Nodename: 'ip-172-30-0-43.ec2.internal'

Datacenter:'dc1'

Server:true (bootstrap: true)

ClientAddr: 127.0.0.1 (HTTP: 8500, HTTPS: -1, DNS: 8600, RPC: 8400)

ClusterAddr: 172.30.0.43 (LAN: 8301, WAN: 8302)

Gossipencrypt: false, RPC-TLS: false, TLS-Incoming: false

Atlas:<disabled>

......（省略）......

4. 檢視，成員info等

[[email protected]]# ./consul members

Node Address Status Type Build Protocol DC

ip-172-30-0-43.ec2.internal 172.30.0.43:8301 alive server 0.6.4 2 dc1

[[email protected]]# ./consul members -detailed

Node Address Status Tags

ip-172-30-0-43.ec2.internal 172.30.0.43:8301 alive bootstrap=1,build=0.6.4:26a0ef8c,dc=dc1,port=8300,role=consul,vsn=2,vsn_max=3,vsn_min=1

[[email protected]]# ./consul info

agent:

check_monitors= 0

check_ttls= 0

checks= 0

services= 1

build:

......（省略）......

二）服務的註冊與發現

1. 節點的基本情況

兩臺Node：

ip-172-30-0-43 RedHat7.2 172.30.0.43Server

ip-172-30-0-89 Amazon(4.1.10)172.30.0.89 Server

2. 執行的主要命令

引數-bootstrap-expect=2指明 是兩臺server

/home/consul/consulagent -server -bootstrap-expect=2 -data-dir /tmp/consul-node=ip-172-30-0-43 -bind=172.30.0.43 -dc=dc1

/home/consul/consulagent -server -bootstrap-expect=2 -data-dir /tmp/consul-node=ip-172-30-0-89 -bind=172.30.0.89 -dc=dc1

/home/consul/consuljoin 172.30.0.89

3. 控制檯輸出

[[email protected]]# /home/consul/consul agent -server -bootstrap-expect=2 -data-dir/tmp/consul -node=ip-172-30-0-43 -bind=172.30.0.43 -dc=dc1

==>WARNING: Expect Mode enabled, expecting 2 servers

==>Starting Consul agent...

==>Starting Consul agent RPC...

==>Consul agent running!

Nodename: 'ip-172-30-0-43'

Datacenter:'dc1'

Server:true (bootstrap: false)

ClientAddr: 127.0.0.1 (HTTP: 8500, HTTPS: -1, DNS: 8600, RPC: 8400)

ClusterAddr: 172.30.0.43 (LAN: 8301, WAN: 8302)

Gossipencrypt: false, RPC-TLS: false, TLS-Incoming: false

Atlas:<disabled>

==>Log data will now stream in as it occurs:

2016/05/1601:48:46 [INFO] serf: EventMemberJoin: ip-172-30-0-43 172.30.0.43

2016/05/1601:48:46 [INFO] serf: EventMemberJoin: ip-172-30-0-43.dc1 172.30.0.43

2016/05/1601:48:46 [INFO] raft: Node at 172.30.0.43:8300 [Follower] enteringFollower state

2016/05/1601:48:46 [INFO] consul: adding LAN server ip-172-30-0-43 (Addr:172.30.0.43:8300) (DC: dc1)

2016/05/1601:48:46 [INFO] consul: adding WAN server ip-172-30-0-43.dc1 (Addr:172.30.0.43:8300) (DC: dc1)

2016/05/1601:48:46 [ERR] agent: failed to sync remote state: No cluster leader

2016/05/1601:48:47 [WARN] raft: EnableSingleNode disabled, and no known peers.Aborting election.

2016/05/1601:48:56 [INFO] agent.rpc: Accepted client: 127.0.0.1:41616

2016/05/1601:48:56 [INFO] agent: (LAN) joining: [172.30.0.89]

2016/05/1601:48:56 [INFO] serf: EventMemberJoin: ip-172-30-0-89 172.30.0.89

2016/05/1601:48:56 [INFO] agent: (LAN) joined: 1 Err: <nil>

2016/05/1601:48:56 [INFO] consul: adding LAN server ip-172-30-0-89 (Addr:172.30.0.89:8300) (DC: dc1)

2016/05/1601:48:56 [INFO] consul: Attempting bootstrap with nodes:[172.30.0.43:8300 172.30.0.89:8300]

2016/05/1601:48:57 [INFO] consul: New leader elected: ip-172-30-0-89

2016/05/1601:49:00 [INFO] agent: Synced service 'consul'

[[email protected]]# /home/consul/consul agent -server -bootstrap-expect=2 -data-dir/tmp/consul -node=ip-172-30-0-89 -bind=172.30.0.89 -dc=dc1

==>WARNING: Expect Mode enabled, expecting 2 servers

==>Starting Consul agent...

==>Starting Consul agent RPC...

==>Consul agent running!

Nodename: 'ip-172-30-0-89'

Datacenter:'dc1'

Server:true (bootstrap: false)

ClientAddr: 127.0.0.1 (HTTP: 8500, HTTPS: -1, DNS: 8600, RPC: 8400)

ClusterAddr: 172.30.0.89 (LAN: 8301, WAN: 8302)

Gossipencrypt: false, RPC-TLS: false, TLS-Incoming: false

Atlas:<disabled>

==>Log data will now stream in as it occurs:

2016/05/1605:48:50 [INFO] serf: EventMemberJoin: ip-172-30-0-89 172.30.0.89

2016/05/1605:48:50 [INFO] serf: EventMemberJoin: ip-172-30-0-89.dc1 172.30.0.89

2016/05/1605:48:50 [INFO] raft: Node at 172.30.0.89:8300 [Follower] enteringFollower state

2016/05/1605:48:50 [INFO] consul: adding LAN server ip-172-30-0-89 (Addr:172.30.0.89:8300) (DC: dc1)

2016/05/1605:48:50 [INFO] consul: adding WAN server ip-172-30-0-89.dc1 (Addr:172.30.0.89:8300) (DC: dc1)

2016/05/1605:48:50 [ERR] agent: failed to sync remote state: No cluster leader

2016/05/1605:48:51 [WARN] raft: EnableSingleNode disabled, and no known peers.Aborting election.

2016/05/1605:48:56 [INFO] serf: EventMemberJoin: ip-172-30-0-43 172.30.0.43

2016/05/1605:48:56 [INFO] consul: adding LAN server ip-172-30-0-43 (Addr:172.30.0.43:8300) (DC: dc1)

2016/05/1605:48:56 [INFO] consul: Attempting bootstrap with nodes:[172.30.0.89:8300 172.30.0.43:8300]

2016/05/1605:48:57 [WARN] raft: Heartbeat timeout reached, starting election

2016/05/1605:48:57 [INFO] raft: Node at 172.30.0.89:8300 [Candidate] enteringCandidate state

2016/05/1605:48:57 [INFO] raft: Election won. Tally: 2

2016/05/1605:48:57 [INFO] raft: Node at 172.30.0.89:8300 [Leader] enteringLeader state

2016/05/1605:48:57 [INFO] consul: cluster leadership acquired

2016/05/1605:48:57 [INFO] consul: New leader elected: ip-172-30-0-89

2016/05/1605:48:57 [INFO] raft: pipelining replication to peer 172.30.0.43:8300

2016/05/1605:48:57 [INFO] consul: member 'ip-172-30-0-89' joined, markinghealth alive

2016/05/1605:48:57 [INFO] consul: member 'ip-172-30-0-43' joined, markinghealth alive

2016/05/1605:48:59 [INFO] agent: Synced service 'consul'

[[email protected]~]# /home/consul/consul join 172.30.0.89

Successfullyjoined cluster by contacting 1 nodes.

[[email protected]~]# /home/consul/consul members

Node Address Status Type Build Protocol DC

ip-172-30-0-43 172.30.0.43:8301 alive server 0.6.4 2 dc1

ip-172-30-0-89 172.30.0.89:8301 alive server 0.6.4 2 dc1

[[email protected]~]# tree /tmp/consul/

/tmp/consul/

├── checkpoint-signature

├── raft

│   ├── peers.json

│   ├── raft.db

│   └── snapshots

└── serf

├── local.snapshot

└── remote.snapshot

3 directories, 5 files

輸入Ctrl+ C 後，停止服務， 輸出如下：

^C==>Caught signal: interrupt

==>Gracefully shutting down agent...

2016/05/1603:03:30 [INFO] consul: server starting leave

2016/05/1603:03:30 [INFO] serf: EventMemberLeave: ip-172-30-0-43.dc1172.30.0.43

2016/05/1603:03:30 [INFO] consul: removing WAN server ip-172-30-0-43.dc1 (Addr:172.30.0.43:8300) (DC: dc1)

2016/05/1603:03:31 [INFO] serf: EventMemberLeave: ip-172-30-0-43 172.30.0.43

2016/05/1603:03:31 [INFO] consul: removing LAN server ip-172-30-0-43 (Addr:172.30.0.43:8300) (DC: dc1)

2016/05/1603:03:31 [INFO] raft: Removed ourself, transitioning to follower

2016/05/1603:03:32 [INFO] agent: requesting shutdown

2016/05/1603:03:32 [INFO] consul: shutting down server

2016/05/1603:03:32 [ERR] dns: error starting tcp server: accept tcp127.0.0.1:8600: use of closed network connection

2016/05/1603:03:32 [INFO] agent: shutdown complete

4. 儲存值

利用開啟的8500http服務，儲存某些值。

[[email protected]]# curl -X PUT -d 'bar'http://localhost:8500/v1/kv/foo

true[[email protected]]#

[[email protected]]# curlhttp://localhost:8500/v1/kv/foo

[{"LockIndex":0,"Key":"foo","Flags":0,"Value":"YmFy","CreateIndex":144,"ModifyIndex":144}][[email protected]]#

[[email protected]]# echo "YmFy" | base64 --decode

bar[[email protected]]#

5. 其他

重啟，但加上-rejoin命令：

如：

/home/consul/consulagent -server -bootstrap-expect=2 -data-dir /tmp/consul-node=ip-172-30-0-43 -bind=172.30.0.43 -dc=dc1 -rejoin

退出， 使用consul leave 命令

三）進一步的思考與問題

1. 幾種一致性演算法或者相關概念

GOSSIP，CONSENSUS, SERF

2. 相關的產品

ZooKeeper, doozerd, etcd

Chef, Puppet, etc.

Nagios, Sensu

SkyDNS

SmartStack

Serf

3. 多資料中心，

延遲？ 配置？

如何寫入資料？指令碼 （curl 寫http請求？）

分裂？一個數據中心， 分裂成兩個或多個

4. 某一個server退出（leave命令）重新加入， 有問題，

不能正確選舉leader ？

5. 發現IBM的一些資料如：

藉助Consul和Docker支援即插即用的服務發現(servicediscovery)

準備進一步學習....