[FLINK-12547] Deadlock when the task thread downloads jars using BlobClient

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.8.0
• Fix Version/s: 1.8.1, 1.9.0
• Component/s: Runtime / Coordination
• Labels: pull-request-available
• Assignee: Haibo Sun
• Reporter: Haibo Sun
• Created: 17/May/19 14:16
• Updated: 04/Jun/19 02:42
• Resolved: 03/Jun/19 13:06

Description

The jstack is as follows (this jstack is from an old Flink version, but the master branch has the same problem).

"Source: Custom Source (76/400)" #68 prio=5 os_prio=0 tid=0x00007f8139cd3000 nid=0xe2 runnable [0x00007f80da5fd000]
java.lang.Thread.State: RUNNABLE
at java.net.SocketInputStream.socketRead0(Native Method)
at java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
at java.net.SocketInputStream.read(SocketInputStream.java:170)
at java.net.SocketInputStream.read(SocketInputStream.java:141)
at org.apache.flink.runtime.blob.BlobInputStream.read(BlobInputStream.java:152)
at org.apache.flink.runtime.blob.BlobInputStream.read(BlobInputStream.java:140)
at org.apache.flink.runtime.blob.BlobClient.downloadFromBlobServer(BlobClient.java:164)
at org.apache.flink.runtime.blob.AbstractBlobCache.getFileInternal(AbstractBlobCache.java:181)
at org.apache.flink.runtime.blob.PermanentBlobCache.getFile(PermanentBlobCache.java:206)
at org.apache.flink.runtime.execution.librarycache.BlobLibraryCacheManager.registerTask(BlobLibraryCacheManager.java:120)
- locked <0x000000062cf2a188> (a java.lang.Object)
at org.apache.flink.runtime.taskmanager.Task.createUserCodeClassloader(Task.java:968)
at org.apache.flink.runtime.taskmanager.Task.run(Task.java:604)
at java.lang.Thread.run(Thread.java:834)

Locked ownable synchronizers:
- None

 

The reason is that SO_TIMEOUT is not set in the socket connection of the blob client. When the network packet loss seriously due to the high CPU load of the machine, the blob client connection fails to perceive that the server has been disconnected, which results in blocking in the native method. 

Issue Links

• relates to: FLINK-12426 TM occasionally hang in deploying state
• links to: GitHub Pull Request #8484