[ACCUMULO-4060] Transient ZooKeeper connection issues kills FATE Runner threads

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.6.4, 1.7.0
• Fix Version/s: 1.6.5, 1.7.1, 1.8.0
• Component/s: fate, master
• Assignee: Josh Elser
• Reporter: Josh Elser
• Created: 19/Nov/15 03:30
• Updated: 03/Jun/16 18:11
• Resolved: 09/Dec/15 17:00

Description

Noticed this the following on a 6 node Accumulo cluster with Kerberos and quality of protection set to auth-conf (wire encryption). The cluster appeared to be up and running – healthy. Attempts to create a table via the shell was hung in the CreateTableCommand, polling on the FATE operation. After a few minutes, it made no progress.

Inspecting the FATE transactions showed that there were (multiple) FATE ops running, but none where locked or locking any tables, nor making any progress.

This lead me to inspect the Master's log to figure out why it wasn't making any progress, and, to my joy, I found the following:

2015-11-18 23:18:30,784 [fate.Fate] ERROR: Thread "Repo runner 0" died org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /accumulo/a1af6ffa-720b-4ec3-8198-5891010294a5/fate
java.lang.RuntimeException: org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /accumulo/a1af6ffa-720b-4ec3-8198-5891010294a5/fate
        at org.apache.accumulo.fate.ZooStore.reserve(ZooStore.java:189)
        at org.apache.accumulo.fate.AgeOffStore.reserve(AgeOffStore.java:158)
        at org.apache.accumulo.fate.Fate$TransactionRunner.run(Fate.java:60)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at org.apache.accumulo.fate.util.LoggingRunnable.run(LoggingRunnable.java:35)
        at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /accumulo/a1af6ffa-720b-4ec3-8198-5891010294a5/fate
        at org.apache.zookeeper.KeeperException.create(KeeperException.java:99)
        at org.apache.zookeeper.KeeperException.create(KeeperException.java:51)
        at org.apache.zookeeper.ZooKeeper.getChildren(ZooKeeper.java:1472)
        at org.apache.zookeeper.ZooKeeper.getChildren(ZooKeeper.java:1500)
        at org.apache.accumulo.fate.zookeeper.ZooReader.getChildren(ZooReader.java:151)
        at org.apache.accumulo.fate.ZooStore.reserve(ZooStore.java:128)
        ... 6 more
2015-11-18 23:18:30,783 [fate.Fate] ERROR: Thread "Repo runner 2" died org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /accumulo/a1af6ffa-720b-4ec3-8198-5891010294a5/fate
java.lang.RuntimeException: org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /accumulo/a1af6ffa-720b-4ec3-8198-5891010294a5/fate
        at org.apache.accumulo.fate.ZooStore.reserve(ZooStore.java:189)
        at org.apache.accumulo.fate.AgeOffStore.reserve(AgeOffStore.java:158)
        at org.apache.accumulo.fate.Fate$TransactionRunner.run(Fate.java:60)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at org.apache.accumulo.fate.util.LoggingRunnable.run(LoggingRunnable.java:35)
        at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /accumulo/a1af6ffa-720b-4ec3-8198-5891010294a5/fate
        at org.apache.zookeeper.KeeperException.create(KeeperException.java:99)
        at org.apache.zookeeper.KeeperException.create(KeeperException.java:51)
        at org.apache.zookeeper.ZooKeeper.getChildren(ZooKeeper.java:1472)
        at org.apache.zookeeper.ZooKeeper.getChildren(ZooKeeper.java:1500)
        at org.apache.accumulo.fate.zookeeper.ZooReader.getChildren(ZooReader.java:151)
        at org.apache.accumulo.fate.ZooStore.reserve(ZooStore.java:128)
        ... 6 more
2015-11-18 23:18:30,787 [fate.Fate] ERROR: Thread "Repo runner 1" died org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /accumulo/a1af6ffa-720b-4ec3-8198-5891010294a5/fate
java.lang.RuntimeException: org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /accumulo/a1af6ffa-720b-4ec3-8198-5891010294a5/fate
        at org.apache.accumulo.fate.ZooStore.reserve(ZooStore.java:189)
        at org.apache.accumulo.fate.AgeOffStore.reserve(AgeOffStore.java:158)
        at org.apache.accumulo.fate.Fate$TransactionRunner.run(Fate.java:60)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at org.apache.accumulo.fate.util.LoggingRunnable.run(LoggingRunnable.java:35)
        at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /accumulo/a1af6ffa-720b-4ec3-8198-5891010294a5/fate
        at org.apache.zookeeper.KeeperException.create(KeeperException.java:99)
        at org.apache.zookeeper.KeeperException.create(KeeperException.java:51)
        at org.apache.zookeeper.ZooKeeper.getChildren(ZooKeeper.java:1472)
        at org.apache.zookeeper.ZooKeeper.getChildren(ZooKeeper.java:1500)
        at org.apache.accumulo.fate.zookeeper.ZooReader.getChildren(ZooReader.java:151)
        at org.apache.accumulo.fate.ZooStore.reserve(ZooStore.java:128)
        ... 6 more
2015-11-18 23:18:30,787 [fate.Fate] ERROR: Thread "Repo runner 3" died org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /accumulo/a1af6ffa-720b-4ec3-8198-5891010294a5/fate
java.lang.RuntimeException: org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /accumulo/a1af6ffa-720b-4ec3-8198-5891010294a5/fate
        at org.apache.accumulo.fate.ZooStore.reserve(ZooStore.java:189)
        at org.apache.accumulo.fate.AgeOffStore.reserve(AgeOffStore.java:158)
        at org.apache.accumulo.fate.Fate$TransactionRunner.run(Fate.java:60)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at org.apache.accumulo.fate.util.LoggingRunnable.run(LoggingRunnable.java:35)
        at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = ConnectionLoss for /accumulo/a1af6ffa-720b-4ec3-8198-5891010294a5/fate
        at org.apache.zookeeper.KeeperException.create(KeeperException.java:99)
        at org.apache.zookeeper.KeeperException.create(KeeperException.java:51)
        at org.apache.zookeeper.ZooKeeper.getChildren(ZooKeeper.java:1472)
        at org.apache.zookeeper.ZooKeeper.getChildren(ZooKeeper.java:1500)
        at org.apache.accumulo.fate.zookeeper.ZooReader.getChildren(ZooReader.java:151)
        at org.apache.accumulo.fate.ZooStore.reserve(ZooStore.java:128)
        ... 6 more

This happened at the end of a ~30s period of difficulties in the Master communicating with ZooKeeper. I've yet to investigate why this pause happened, but the fact that the FATE runner threads died and the Master kept running is no good.

Issue Links

• links to: GitHub Pull Request #52
• links to: PR