Oleksandr Shevchenko created HADOOP-15865:
---------------------------------------------
Summary: ConcurrentModificationException in
Configuration.overlay() method
Key: HADOOP-15865
URL: https://issues.apache.org/jira/browse/HADOOP-15865
Project: Hadoop Common
Issue Type: Bug
Reporter: Oleksandr Shevchenko
Assignee: Oleksandr Shevchenko
Configuration.overlay() is not thread-safe and can be the cause of
ConcurrentModificationException since we use iteration over Properties object.
{code}
private void overlay(Properties to, Properties from) {
for (Entry<Object, Object> entry: from.entrySet()) {
to.put(entry.getKey(), entry.getValue());
}
}
{code}
Properties class is thread-safe but iterator is not. We should manually
synchronize on the returned set of entries which we use for iteration.
We faced with ResourceManger fails during recovery caused by
ConcurrentModificationException:
{noformat}
2018-10-12 08:00:56,968 INFO org.apache.hadoop.service.AbstractService: Service
ResourceManager failed in state STARTED; cause:
java.util.ConcurrentModificationException
java.util.ConcurrentModificationException
at java.util.Hashtable$Enumerator.next(Hashtable.java:1383)
at org.apache.hadoop.conf.Configuration.overlay(Configuration.java:2801)
at org.apache.hadoop.conf.Configuration.loadResource(Configuration.java:2696)
at org.apache.hadoop.conf.Configuration.loadResources(Configuration.java:2632)
at org.apache.hadoop.conf.Configuration.getProps(Configuration.java:2528)
at org.apache.hadoop.conf.Configuration.get(Configuration.java:1062)
at
org.apache.hadoop.conf.Configuration.getStringCollection(Configuration.java:1914)
at
org.apache.hadoop.security.alias.CredentialProviderFactory.getProviders(CredentialProviderFactory.java:53)
at
org.apache.hadoop.conf.Configuration.getPasswordFromCredentialProviders(Configuration.java:2043)
at org.apache.hadoop.conf.Configuration.getPassword(Configuration.java:2023)
at
org.apache.hadoop.yarn.webapp.util.WebAppUtils.getPassword(WebAppUtils.java:452)
at
org.apache.hadoop.yarn.webapp.util.WebAppUtils.loadSslConfiguration(WebAppUtils.java:428)
at org.apache.hadoop.yarn.webapp.WebApps$Builder.start(WebApps.java:293)
at
org.apache.hadoop.yarn.server.resourcemanager.ResourceManager.startWepApp(ResourceManager.java:1017)
at
org.apache.hadoop.yarn.server.resourcemanager.ResourceManager.serviceStart(ResourceManager.java:1117)
at org.apache.hadoop.service.AbstractService.start(AbstractService.java:193)
at
org.apache.hadoop.yarn.server.resourcemanager.ResourceManager.main(ResourceManager.java:1251)
2018-10-12 08:00:56,968 INFO
org.apache.hadoop.yarn.server.resourcemanager.security.RMDelegationTokenSecretManager:
removing RMDelegation token with sequence number: 3489914
2018-10-12 08:00:56,968 INFO
org.apache.hadoop.yarn.server.resourcemanager.recovery.RMStateStore: Removing
RMDelegationToken and SequenceNumber
2018-10-12 08:00:56,968 INFO
org.apache.hadoop.yarn.server.resourcemanager.recovery.FileSystemRMStateStore:
Removing RMDelegationToken_3489914
2018-10-12 08:00:56,969 INFO org.apache.hadoop.ipc.Server: Stopping server on
8032
{noformat}
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