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Posted to issues@sentry.apache.org by "Vamsee Yarlagadda (JIRA)" <ji...@apache.org> on 2017/02/03 04:21:51 UTC
[jira] [Created] (SENTRY-1621) HMSFollower to retry connecting to
HMS upon connection loss
Vamsee Yarlagadda created SENTRY-1621:
-----------------------------------------
Summary: HMSFollower to retry connecting to HMS upon connection loss
Key: SENTRY-1621
URL: https://issues.apache.org/jira/browse/SENTRY-1621
Project: Sentry
Issue Type: Sub-task
Components: Hdfs Plugin
Reporter: Vamsee Yarlagadda
Assignee: Vamsee Yarlagadda
Fix For: sentry-ha-redesign
[This code in HMSFollower|https://github.com/apache/sentry/blob/sentry-ha-redesign/sentry-provider/sentry-provider-db/src/main/java/org/apache/sentry/service/thrift/HMSFollower.java#L120-L183] has bugs in implementing logic that's preventing secure HMS connection from taking place.
{code}
String principal, keytab;
//TODO: Is this the right(standard) way to create a HMS client? HiveMetastoreClientFactoryImpl?
//TODO: Check if HMS is using kerberos instead of relying on Sentry conf
//TODO: Handle TGT renewals
kerberos = ServiceConstants.ServerConfig.SECURITY_MODE_KERBEROS.equalsIgnoreCase(
conf.get(ServiceConstants.ServerConfig.SECURITY_MODE, ServiceConstants.ServerConfig.SECURITY_MODE_KERBEROS).trim());
if (kerberos) {
LOGGER.info("Making a kerberos connection to HMS");
//TODO: Is this needed? Use Hadoop libraries to translate the _HOST placeholder with actual hostname
//Validate principal
principal = Preconditions.checkNotNull(ServiceConstants.ServerConfig.PRINCIPAL,
ServiceConstants.ServerConfig.PRINCIPAL + " is required");
LOGGER.info("Using kerberos principal: " + principal);
final String[] principalParts = SaslRpcServer.splitKerberosName(principal);
Preconditions.checkArgument(principalParts.length == 3,
"Kerberos principal should have 3 parts: " + principal);
keytab = Preconditions.checkNotNull(conf.get(ServiceConstants.ServerConfig.KEY_TAB),
ServiceConstants.ServerConfig.KEY_TAB + " is required");
File keytabFile = new File(keytab);
Preconditions.checkState(keytabFile.isFile() && keytabFile.canRead(),
"Keytab " + keytab + " does not exist or is not readable.");
boolean establishedKerberosContext = false;
int attempt = 1;
while(establishedKerberosContext) {
try {
kerberosContext = new SentryKerberosContext(principal, keytab, true);
establishedKerberosContext = true;
LOGGER.info("Established kerberos context, will now connect to HMS");
} catch (LoginException e) {
//Kerberos login failed
if( attempt > maxRetriesForLogin ) {
throw e;
}
attempt++;
}
}
boolean establishedConnection = false;
attempt = 1;
while(establishedConnection) {
try {
client = Subject.doAs(kerberosContext.getSubject(), new PrivilegedExceptionAction<HiveMetaStoreClient>() {
@Override
public HiveMetaStoreClient run() throws Exception {
return new HiveMetaStoreClient(hiveConf);
}
});
LOGGER.info("Secure connection established with HMS");
} catch (PrivilegedActionException e) {
if( attempt > maxRetriesForConnection ) {
//We should just retry as it is possible that HMS is not ready yet to receive requests
//TODO: How do we differentiate between kerberos problem versus HMS not being up?
LOGGER.error("Cannot connect to HMS", e);
}
attempt++;
}
}
} else {
//This is only for testing purposes. Sentry strongly recommends strong authentication
client = new HiveMetaStoreClient(hiveConf);
LOGGER.info("Non secure connection established with HMS");
}
return client;
}
{code}
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