我正在將 Windows 上的 kafka/zookeeper 叢集遷移到 Debian wheezy。
- Java版本：1.7.0_80
- Debian 版本：7.9
- Zookeeper版本：3.3.5+dfsg1-2 0
- 卡夫卡版本：2.10-0.8.2.1
如果我使用其他 Debian 伺服器的 IP 位址在 Debian 伺服器上設定 Zookeeper，則一切正常。如果我改用 DNS 名稱，則 Debian 伺服器上的領導者選舉會失敗。
在 Debian 伺服器上，我可以使用「host」命令來尋找任何其他 Debian 伺服器的 IP，因此 DNS 解析正常。
一切都是自動化的：伺服器建立、Debian 安裝、zookeeper 安裝、zookeeper 設定；因此，手動配置錯誤的視窗處於最低限度，並且易於重現或更改。
使用clientPortAddress=DNSNAME沒有任何區別；它仍然失敗。 iptables 中沒有配置任何內容。這些伺服器之間沒有防火牆。
其中伺服器1-3為Windows 2012R2伺服器，伺服器4-6為Debian伺服器。
此配置有效：
server.1=testkafka400:2888:3888
server.2=testkafka401:2888:3888
server.3=testkafka402:2888:3888
server.4=10.1.132.152:2888:3888
server.5=10.1.132.153:2888:3888
server.6=10.1.132.154:2888:3888
此配置不起作用：
server.1=testkafka400:2888:3888
server.2=testkafka401:2888:3888
server.3=testkafka402:2888:3888
server.4=testkafka403:2888:3888
server.5=testkafka404:2888:3888
server.6=testkafka405:2888:3888
當我使用 DNS 名稱時，我得到以下輸出 - 其中異常會重複出現。請注意，以下日誌來自包含以下內容的叢集設定：僅有的Debian 伺服器，使用 DNS 名稱，以便進行測試。如果我切換到IP，集群就可以工作並且可以進行選舉。
[2015-11-03 13:55:52,309] INFO Reading configuration from: /etc/zookeeper/config/zookeeper.properties (org.apache.zookeeper.server.quorum.QuorumPeerConfig)
[2015-11-03 13:55:52,322] INFO Defaulting to majority quorums (org.apache.zookeeper.server.quorum.QuorumPeerConfig)
[2015-11-03 13:55:52,344] INFO autopurge.snapRetainCount set to 3 (org.apache.zookeeper.server.DatadirCleanupManager)
[2015-11-03 13:55:52,344] INFO autopurge.purgeInterval set to 24 (org.apache.zookeeper.server.DatadirCleanupManager)
[2015-11-03 13:55:52,345] INFO Purge task started. (org.apache.zookeeper.server.DatadirCleanupManager)
[2015-11-03 13:55:52,454] INFO Purge task completed. (org.apache.zookeeper.server.DatadirCleanupManager)
[2015-11-03 13:55:52,472] INFO Starting quorum peer (org.apache.zookeeper.server.quorum.QuorumPeerMain)
[2015-11-03 13:55:52,581] INFO binding to port 0.0.0.0/0.0.0.0:2181 (org.apache.zookeeper.server.NIOServerCnxnFactory)
[2015-11-03 13:55:52,601] INFO tickTime set to 3000 (org.apache.zookeeper.server.quorum.QuorumPeer)
[2015-11-03 13:55:52,601] INFO minSessionTimeout set to -1 (org.apache.zookeeper.server.quorum.QuorumPeer)
[2015-11-03 13:55:52,601] INFO maxSessionTimeout set to -1 (org.apache.zookeeper.server.quorum.QuorumPeer)
[2015-11-03 13:55:52,601] INFO initLimit set to 20 (org.apache.zookeeper.server.quorum.QuorumPeer)
[2015-11-03 13:55:52,626] INFO Reading snapshot /etc/zookeeper/data/version-2/snapshot.0 (org.apache.zookeeper.server.persistence.FileSnap)
[2015-11-03 13:55:52,675] INFO My election bind port: testkafka403.prod.local/127.0.1.1:3888 (org.apache.zookeeper.server.quorum.QuorumCnxManager)
[2015-11-03 13:55:52,713] INFO LOOKING (org.apache.zookeeper.server.quorum.QuorumPeer)
[2015-11-03 13:55:52,715] INFO New election. My id = 4, proposed zxid=0x100000014 (org.apache.zookeeper.server.quorum.FastLeaderElection)
[2015-11-03 13:55:52,717] INFO Notification: 1 (message format version), 4 (n.leader), 0x100000014 (n.zxid), 0x1 (n.round), LOOKING (n.state), 4 (n.sid), 0x1 (n.peerEpoch) LOOKING (my state) (org.apache.zookeeper.server.quorum.FastLeaderElection)
[2015-11-03 13:55:52,732] WARN Cannot open channel to 5 at election address testkafka404.prod.local/10.1.132.153:3888 (org.apache.zookeeper.server.quorum.QuorumCnxManager)
java.net.SocketTimeoutException
at java.net.SocksSocketImpl.remainingMillis(SocksSocketImpl.java:111)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:579)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectOne(QuorumCnxManager.java:368)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.toSend(QuorumCnxManager.java:341)
at org.apache.zookeeper.server.quorum.FastLeaderElection$Messenger$WorkerSender.process(FastLeaderElection.java:449)
at org.apache.zookeeper.server.quorum.FastLeaderElection$Messenger$WorkerSender.run(FastLeaderElection.java:430)
at java.lang.Thread.run(Thread.java:745)
[2015-11-03 13:55:52,737] WARN Cannot open channel to 6 at election address testkafka405.prod.local/10.1.132.154:3888 (org.apache.zookeeper.server.quorum.QuorumCnxManager)
java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:579)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectOne(QuorumCnxManager.java:368)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.toSend(QuorumCnxManager.java:341)
at org.apache.zookeeper.server.quorum.FastLeaderElection$Messenger$WorkerSender.process(FastLeaderElection.java:449)
at org.apache.zookeeper.server.quorum.FastLeaderElection$Messenger$WorkerSender.run(FastLeaderElection.java:430)
at java.lang.Thread.run(Thread.java:745)
[2015-11-03 13:55:52,919] WARN Cannot open channel to 6 at election address testkafka405.prod.local/10.1.132.154:3888 (org.apache.zookeeper.server.quorum.QuorumCnxManager)
java.net.ConnectException: Connection refused
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:579)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectOne(QuorumCnxManager.java:368)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectAll(QuorumCnxManager.java:402)
at org.apache.zookeeper.server.quorum.FastLeaderElection.lookForLeader(FastLeaderElection.java:840)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:762)
我們確實希望能夠使用 DNS 名稱，但不知道應該從哪裡開始尋找解決方案。也許我們錯過了安裝或啟動重要的 Debian 或 Java 功能？
答案1
好的，我知道這裡發生了什麼事。當我嘗試在 Linux 虛擬機器上的 Vagrant 中設定 3 節點 Spring-XD 叢集時，我看到了相同的問題。
此配置有效：
server.1=172.28.128.3:2888:3888
server.2=172.28.128.4:2888:3888
server.3=172.28.128.7:2888:3888
但這個沒有：
server.1=spring-xd-1:2888:3888
server.2=spring-xd-2:2888:3888
server.3=spring-xd-3:2888:3888
「確鑿的證據」是我的動物園管理員日誌中的這一行：
2015-11-26 20:48:31,439 [myid:1] - INFO [Thread-2:QuorumCnxManager$Listener@504] - 我選擇綁定埠：spring-xd-1/127.0.0.1:3888
那麼，Zookeeper為什麼要將選舉埠綁定在環回介面上呢？出色地...
我的/etc/hosts其中一台虛擬機器看起來像這樣：
127.0.0.1 spring-xd-1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
## vagrant-hostmanager-start
172.28.128.3 spring-xd-1
172.28.128.4 spring-xd-2
172.28.128.7 spring-xd-3
## vagrant-hostmanager-end
127.0.0.1我從行中刪除了主機名/etc/hosts，並在所有 3 個節點上退回了 Zookeeper 服務，並且嘭！一切都變成玫瑰花。所以，現在每台機器上的主機檔案如下所示：
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
## vagrant-hostmanager-start
172.28.128.3 spring-xd-1
172.28.128.4 spring-xd-2
172.28.128.7 spring-xd-3
## vagrant-hostmanager-end
我猜您在 Windows 上沒有看到這個問題，因為C:\Windows\System32\drivers\etc\hosts預設情況下主機檔案 ( ) 沒有條目。透過新增類似的127.0.0.1行，您應該能夠在 Windows 上重現問題。
我稱之為動物園管理員錯誤。編輯主機檔案足以證明問題並在 Vagrant 中修復它，但我不會推薦它用於任何“真實”環境。
編輯：根據http://ccl.cse.nd.edu/operations/condor/hostname.shtml，這似乎是 Linux 上的叢集應用程式的一個相當常見的問題，建議按照我上面的描述編輯主機檔案。但是，那有關集群設定的 Zookeeper 文檔沒有提到它。