閱讀本文大約需要3分鐘。
最近在學習微服務，遇到了很多問題，今天又遇到了個連接zookeeper報錯的問題，在此記錄下。
如下爲：學生課程管理系統簡單微服務架構圖：
各個服務docker化以後，用docker-compose啓動，其中docker-compose.yml文件如下：
version: "3"
services:
message-service:
image: message-thrift-python-service:latest
user-service:
image: user-thrift-service:latest
command:
- "--mysql.address=192.168.1.103"
user-edge-service:
image: user-edge-service:latest
links:
- user-service
- message-service
command:
- "--redis.address=192.168.1.103"
course-service:
image: course-service:latest
links:
- user-service
command:
- "--mysql.address=192.168.1.103"
- "--zookeeper.address=192.168.1.103"
course-edge-service:
image: course-edge-service:latest
links:
- user-edge-service
command:
- "--zookeeper.address=192.168.1.103"
api-gateway-zuul:
image: api-gateway-zuul:latest
links:
- course-edge-service
- user-edge-service
ports:
- 8080:8080docker-compose up -d啓動後，訪問course-edge-service服務時報錯，日誌裏打印如下錯誤：
2018-10-04 08:32:32.584 INFO 1 --- [168.1.103:2181)] org.apache.zookeeper.ClientCnxn : Opening socket connection to server 192.168.1.103/192.168.1.103:2181. Will not attempt to authenticate using SASL (unknown error)
2018-10-04 08:32:33.590 WARN 1 --- [168.1.103:2181)] org.apache.zookeeper.ClientCnxn : Session 0x0 for server null, unexpected error, closing socket connection and attempting reconnect
java.net.NoRouteToHostException: No route to host
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method) ~[na:1.8.0_181]
at sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:717) ~[na:1.8.0_181]
at org.apache.zookeeper.ClientCnxnSocketNIO.doTransport(ClientCnxnSocketNIO.java:361) ~[zookeeper-3.4.6.jar!/:3.4.6-1569965]
at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1081) ~[zookeeper-3.4.6.jar!/:3.4.6-1569965]於是先docker-compose down掉各服務，暫且單獨啓動course-edge-service單服務看是否同樣報錯：
docker run -ti course-edge-service:latest --zookeeper.address=192.168.1.103
啓動後報同樣的錯。
看報錯日誌應該就是連不上zookeeper，在宿主機上curl zookeeper地址，是通的：
[root@localhost course-edge-service]# curl 192.168.1.103:2181 curl: (52) Empty reply from server
進入zookeeper容器內看zookeeper狀態：
[root@localhost course-edge-service]# docker exec -ti c2803533c4fb bash bash-4.4# cd bin/ bash-4.4# ./zk zkCleanup.sh zkEnv.cmd zkServer.cmd zkTxnLogToolkit.sh zkCli.cmd zkEnv.sh zkServer.sh zkCli.sh zkServer-initialize.sh zkTxnLogToolkit.cmd bash-4.4# ./zkServer.sh status ZooKeeper JMX enabled by default Using config: /conf/zoo.cfg Client port found: 2181. Client address: localhost. Mode: leader bash-4.4#
zookeeper狀態正常。
在course-edge-service的容器內curl zookeeper地址：
[root@localhost course-edge-service]# docker exec -ti 5c993840aeae bash root@5c993840aeae:/# curl 192.168.1.103:2181 curl: (7) Failed to connect to 192.168.1.103 port 2181: No route to host root@5c993840aeae:/# root@5c993840aeae:/# ping 192.168.1.103 PING 192.168.1.103 (192.168.1.103) 56(84) bytes of data. 64 bytes from 192.168.1.103: icmp_seq=1 ttl=64 time=0.255 ms 64 bytes from 192.168.1.103: icmp_seq=2 ttl=64 time=0.163 ms 64 bytes from 192.168.1.103: icmp_seq=3 ttl=64 time=0.164 ms
發現確實有問題。
解決問題：
查看防火牆狀態：
$ systemctl status firewalld.service
● firewalld.service - firewalld - dynamic firewall daemon
Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)
Active: active (running) since Thu 2018-10-04 00:38:32 CST; 15h ago
Main PID: 826 (firewalld)
Memory: 2.4M
CGroup: /system.slice/firewalld.service
└─826 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid關閉防火牆：
$ systemctl stop firewalld.service
course-edge-service的容器內再curl zookeeper地址：
[root@localhost course-edge-service]# docker exec -ti 5c993840aeae bash root@5c993840aeae:/# curl 192.168.1.103:2181 curl: (52) Empty reply from server root@5c993840aeae:/#
重新啓動各個微服務，又報錯如下：
[root@localhost micro-service]# docker-compose up -d Creating network "micro-service_default" with the default driver ERROR: Failed to Setup IP tables: Unable to enable SKIP DNAT rule: (iptables failed: iptables --wait -t nat -I DOCKER -i br-07454d600e41 -j RETURN: iptables: No chain/target/match by that name. (exit status 1))
重啓docker後問題解決：
[root@localhost micro-service]#systemctl restart docker [root@localhost micro-service]# docker-compose up -d Creating network "micro-service_default" with the default driver Creating micro-service_user-service_1_11592de6bbc3 ... done Creating micro-service_message-service_1_b225fa599858 ... done Creating micro-service_user-edge-service_1_4f8b6edf7333 ... done Creating micro-service_course-service_1_69e9bdcbd81e ... done Creating micro-service_course-edge-service_1_81d9188df304 ... done Creating micro-service_api-gateway-zuul_1_e0bdf98eebef ... done