[HADOOP-9085] start namenode failure,bacause pid of namenode pid file is other process pid or thread id before start namenode

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Affects Version/s: 2.0.1-alpha, 2.0.3-alpha
• Component/s: bin, scripts

Environment

NA

• Target Version/s: 2.0.1-alpha, 2.0.2-alpha
• Assignee: Unassigned
• Reporter: liaowenrui
• Created: 23/Nov/12 04:16
• Updated: 06/Feb/18 20:30
• Resolved: 06/Feb/18 20:30

Description

pid of namenode pid file is other process pid or thread id before start namenode,start namenode will failure.because the pid of namenode pid file will be checked use kill -0 command before start namenode in hadoop-daemo.sh script.when pid of namenode pid file is other process pid or thread id,checkt is use kil -0 command,and the kill -0 will return success.it means the namenode is runing.in really,namenode is not runing.

2338 is dead namenode pid
2305 is datanode pid

cqn2:/tmp # kill -0 2338
cqn2:/tmp # ps -wweLo pid,ppid,tid | grep 2338
2305 1 2338

Issue Links

• duplicates: HADOOP-14855 Hadoop scripts may errantly believe a daemon is still running, preventing it from starting
• relates to: HADOOP-9086 Enforce process singleton rules through an exclusive write lock on a file, not a pid file +kill -0,