Setup cross realm trust between two MIT KDC
How to setup cross realm trust between two MIT KDC – In this post, we will see how to setup cross realm trust between two MIT KDC. We can access and copy data from one cluster to another if the cross realm trust is setup correctly.
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In our example, we have 2 clusters with same HDP version(2.4.2.0) and Ambari version(2.2.2.0)
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Cluster 1:
172.26.68.47 hwx-1.hwx.com hwx-1
172.26.68.46 hwx-2.hwx.com hwx-2
172.26.68.45 hwx-3.hwx.com hwx-3
Cluster 2:
172.26.68.48 support-1.support.com support-1
172.26.68.49 support-2.support.com support-2
172.26.68.50 support-3.support.com support-3
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Below are the steps:
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Step 1: Make sure both the clusters are kerberized with MIT KDC. You can use below automated script for configuring Kerberos on HDP.
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Step 2: Please configure /etc/hosts file on both the clusters to have Ip <-> hostname mappings.
Example:
On both clusters /etc/hosts file should look like below:
172.26.68.47 hwx-1.hwx.com hwx-1
172.26.68.46 hwx-2.hwx.com hwx-2
172.26.68.45 hwx-3.hwx.com hwx-3
172.26.68.48 support-1.support.com support-1
172.26.68.49 support-2.support.com support-2
172.26.68.50 support-3.support.com support-3
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Step 3: Configure krb5.conf:
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3.1 Configure [realm] section to add another cluster’s KDC server details – This is required to find KDC to authenticate user which belongs to another cluster.
Example on Cluster1:
[realms]
HWX.COM = {
admin_server = hwx-1.hwx.com
kdc = hwx-1.hwx.com
}
SUPPORT.COM = {
admin_server = support-1.support.com
kdc = support-1.support.com
}
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3.2 Configure [domain_realm] section to add another cluster’s domain <-> realm mapping.[domain_realm]
.hwx.com = HWX.COM
hwx.com = HWX.COM
.support.com = SUPPORT.COM
support.com = SUPPORT.COM
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3.3 Configure [capaths] to add another cluster’s realm[capaths]
HWX.COM = {
SUPPORT.COM = .
}
On Cluster 1, the krb5.conf should look like below:
[libdefaults]
renew_lifetime = 7d
forwardable = true
default_realm = HWX.COM
ticket_lifetime = 24h
dns_lookup_realm = false
dns_lookup_kdc = false
#default_tgs_enctypes = aes des3-cbc-sha1 rc4 des-cbc-md5
#default_tkt_enctypes = aes des3-cbc-sha1 rc4 des-cbc-md5
[logging]
default = FILE:/var/log/krb5kdc.log
admin_server = FILE:/var/log/kadmind.log
kdc = FILE:/var/log/krb5kdc.log
[realms]
HWX.COM = {
admin_server = hwx-1.hwx.com
kdc = hwx-1.hwx.com
}
SUPPORT.COM = {
admin_server = support-1.support.com
kdc = support-1.support.com
}
[domain_realm]
.hwx.com = HWX.COM
hwx.com = HWX.COM
.support.com = SUPPORT.COM
support.com = SUPPORT.COM
[capaths]
HWX.COM = {
SUPPORT.COM = .
}
Note – Please copy modified /etc/krb5.conf to all the nodes in Cluster 1
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Similarly on Cluster2, the krb5.conf should look like below:
[libdefaults]
renew_lifetime = 7d
forwardable = true
default_realm = SUPPORT.COM
ticket_lifetime = 24h
dns_lookup_realm = false
dns_lookup_kdc = false
#default_tgs_enctypes = aes des3-cbc-sha1 rc4 des-cbc-md5
#default_tkt_enctypes = aes des3-cbc-sha1 rc4 des-cbc-md5
[logging]
default = FILE:/var/log/krb5kdc.log
admin_server = FILE:/var/log/kadmind.log
kdc = FILE:/var/log/krb5kdc.log
[realms]
SUPPORT.COM = {
admin_server = support-1.support.com
kdc = support-1.support.com
}
HWX.COM = {
admin_server = hwx-1.hwx.com
kdc = hwx-1.hwx.com
}
[domain_realm]
.hwx.com = HWX.COM
hwx.com = HWX.COM
.support.com = SUPPORT.COM
support.com = SUPPORT.COM
[capaths]
SUPPORT.COM = {
HWX.COM = .
}
Note – Please copy modified /etc/krb5.conf to all the nodes in Cluster 2
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Step 4: Modify below property in hdfs-site.xml on a cluster from where you want to execute distcp command ( specifically speaking - client side )
dfs.namenode.kerberos.principal.pattern=*
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Step 5: Add a common trust principal in both the KDCs. Please keep same password for both the principals
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On Cluster 1 and 2, execute below commands in kadmin utility:
addprinc krbtgt/HWX.COM@SUPPORT.COM
addprinc krbtgt/SUPPORT.COM@HWX.COM
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Step 6: Configure auth_to_local rules on both the clusters:
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On Cluster1, append auth_to_local rules from Cluster2
Example on Cluster 1:
RULE:[1:$1@$0](ambari-qa-hadoop@HWX.COM)s/.*/ambari-qa/
RULE:[1:$1@$0](hdfs-hadoop@HWX.COM)s/.*/hdfs/
RULE:[1:$1@$0](spark-hadoop@HWX.COM)s/.*/spark/
RULE:[1:$1@$0](.*@HWX.COM)s/@.*//
RULE:[2:$1@$0](dn@HWX.COM)s/.*/hdfs/
RULE:[2:$1@$0](hive@HWX.COM)s/.*/hive/
RULE:[2:$1@$0](jhs@HWX.COM)s/.*/mapred/
RULE:[2:$1@$0](jn@HWX.COM)s/.*/hdfs/
RULE:[2:$1@$0](nm@HWX.COM)s/.*/yarn/
RULE:[2:$1@$0](nn@HWX.COM)s/.*/hdfs/
RULE:[2:$1@$0](rm@HWX.COM)s/.*/yarn/
RULE:[2:$1@$0](yarn@HWX.COM)s/.*/yarn/
DEFAULT
RULE:[1:$1@$0](ambari-qa-support@SUPPORT.COM)s/.*/ambari-qa/
RULE:[1:$1@$0](hdfs-support@SUPPORT.COM)s/.*/hdfs/
RULE:[1:$1@$0](spark-support@SUPPORT.COM)s/.*/spark/
RULE:[1:$1@$0](.*@SUPPORT.COM)s/@.*//
RULE:[2:$1@$0](dn@SUPPORT.COM)s/.*/hdfs/
RULE:[2:$1@$0](hive@SUPPORT.COM)s/.*/hive/
RULE:[2:$1@$0](jhs@SUPPORT.COM)s/.*/mapred/
RULE:[2:$1@$0](jn@SUPPORT.COM)s/.*/hdfs/
RULE:[2:$1@$0](nm@SUPPORT.COM)s/.*/yarn/
RULE:[2:$1@$0](nn@SUPPORT.COM)s/.*/hdfs/
RULE:[2:$1@$0](rm@SUPPORT.COM)s/.*/yarn/
RULE:[2:$1@$0](yarn@SUPPORT.COM)s/.*/yarn/
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On Cluster2, append auth_to_local rules from Cluster1
Example on Cluster 2:
RULE:[1:$1@$0](ambari-qa-support@SUPPORT.COM)s/.*/ambari-qa/
RULE:[1:$1@$0](hdfs-support@SUPPORT.COM)s/.*/hdfs/
RULE:[1:$1@$0](spark-support@SUPPORT.COM)s/.*/spark/
RULE:[1:$1@$0](.*@SUPPORT.COM)s/@.*//
RULE:[2:$1@$0](dn@SUPPORT.COM)s/.*/hdfs/
RULE:[2:$1@$0](hive@SUPPORT.COM)s/.*/hive/
RULE:[2:$1@$0](jhs@SUPPORT.COM)s/.*/mapred/
RULE:[2:$1@$0](jn@SUPPORT.COM)s/.*/hdfs/
RULE:[2:$1@$0](nm@SUPPORT.COM)s/.*/yarn/
RULE:[2:$1@$0](nn@SUPPORT.COM)s/.*/hdfs/
RULE:[2:$1@$0](rm@SUPPORT.COM)s/.*/yarn/
RULE:[2:$1@$0](yarn@SUPPORT.COM)s/.*/yarn/
DEFAULT
RULE:[1:$1@$0](ambari-qa-hadoop@HWX.COM)s/.*/ambari-qa/
RULE:[1:$1@$0](hdfs-hadoop@HWX.COM)s/.*/hdfs/
RULE:[1:$1@$0](spark-hadoop@HWX.COM)s/.*/spark/
RULE:[1:$1@$0](.*@HWX.COM)s/@.*//
RULE:[2:$1@$0](dn@HWX.COM)s/.*/hdfs/
RULE:[2:$1@$0](hive@HWX.COM)s/.*/hive/
RULE:[2:$1@$0](jhs@HWX.COM)s/.*/mapred/
RULE:[2:$1@$0](jn@HWX.COM)s/.*/hdfs/
RULE:[2:$1@$0](nm@HWX.COM)s/.*/yarn/
RULE:[2:$1@$0](nn@HWX.COM)s/.*/hdfs/
RULE:[2:$1@$0](rm@HWX.COM)s/.*/yarn/
RULE:[2:$1@$0](yarn@HWX.COM)s/.*/yarn/
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Step 7: Login to Cluster 2, do a kinit by local user and try to access hdfs files of Cluster 1
Example:
hdfs dfs -ls hdfs://hwx-2.hwx.com:8020/tmp
Found 8 items
drwx------ - ambari-qa hdfs 0 2016-07-29 23:24 hdfs://hwx-2.hwx.com:8020/tmp/ambari-qa
drwxr-xr-x - hdfs hdfs 0 2016-07-29 22:02 hdfs://hwx-2.hwx.com:8020/tmp/entity-file-history
drwx-wx-wx - ambari-qa hdfs 0 2016-07-29 23:25 hdfs://hwx-2.hwx.com:8020/tmp/hive
-rwxr-xr-x 3 hdfs hdfs 1414 2016-07-29 23:50 hdfs://hwx-2.hwx.com:8020/tmp/id1aac2d44_date502916
-rwxr-xr-x 3 ambari-qa hdfs 1414 2016-07-29 23:26 hdfs://hwx-2.hwx.com:8020/tmp/idtest.ambari-qa.1469834803.19.in
-rwxr-xr-x 3 ambari-qa hdfs 957 2016-07-29 23:26 hdfs://hwx-2.hwx.com:8020/tmp/idtest.ambari-qa.1469834803.19.pig
drwxr-xr-x - ambari-qa hdfs 0 2016-07-29 23:53 hdfs://hwx-2.hwx.com:8020/tmp/tezsmokeinput
Note – hwx-2.hwx.com is the Active Namenode of Cluster 1.
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You can try copying files from Cluster 2 to Cluster 1 using distcp
Example:
[kuldeepk@support-1 root]$ hadoop distcp hdfs://hwx-1.hwx.com:8020/tmp/test.txt /tmp/
16/07/30 22:03:27 INFO tools.DistCp: Input Options: DistCpOptions{atomicCommit=false, syncFolder=false, deleteMissing=false, ignoreFailures=false, maxMaps=20, sslConfigurationFile='null', copyStrategy='uniformsize', sourceFileListing=null, sourcePaths=[hdfs://hwx-1.hwx.com:8020/tmp/test.txt], targetPath=/tmp, targetPathExists=true, preserveRawXattrs=false}
16/07/30 22:03:27 INFO impl.TimelineClientImpl: Timeline service address: http://support-3.support.com:8188/ws/v1/timeline/
16/07/30 22:03:27 INFO client.RMProxy: Connecting to ResourceManager at support-3.support.com/172.26.68.50:8050
16/07/30 22:03:28 INFO hdfs.DFSClient: Created HDFS_DELEGATION_TOKEN token 20 for kuldeepk on 172.26.68.47:8020
16/07/30 22:03:28 INFO security.TokenCache: Got dt for hdfs://hwx-1.hwx.com:8020; Kind: HDFS_DELEGATION_TOKEN, Service: 172.26.68.47:8020, Ident: (HDFS_DELEGATION_TOKEN token 20 for kuldeepk)
16/07/30 22:03:29 INFO impl.TimelineClientImpl: Timeline service address: http://support-3.support.com:8188/ws/v1/timeline/
16/07/30 22:03:29 INFO client.RMProxy: Connecting to ResourceManager at support-3.support.com/172.26.68.50:8050
16/07/30 22:03:29 INFO hdfs.DFSClient: Created HDFS_DELEGATION_TOKEN token 24 for kuldeepk on ha-hdfs:support
16/07/30 22:03:29 INFO security.TokenCache: Got dt for hdfs://support; Kind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:support, Ident: (HDFS_DELEGATION_TOKEN token 24 for kuldeepk)
16/07/30 22:03:29 INFO mapreduce.JobSubmitter: number of splits:1
16/07/30 22:03:29 INFO mapreduce.JobSubmitter: Submitting tokens for job: job_1469916118318_0003
16/07/30 22:03:29 INFO mapreduce.JobSubmitter: Kind: HDFS_DELEGATION_TOKEN, Service: 172.26.68.47:8020, Ident: (HDFS_DELEGATION_TOKEN token 20 for kuldeepk)
16/07/30 22:03:29 INFO mapreduce.JobSubmitter: Kind: HDFS_DELEGATION_TOKEN, Service: ha-hdfs:support, Ident: (HDFS_DELEGATION_TOKEN token 24 for kuldeepk)
16/07/30 22:03:30 INFO impl.YarnClientImpl: Submitted application application_1469916118318_0003
16/07/30 22:03:31 INFO mapreduce.Job: The url to track the job: http://support-3.support.com:8088/proxy/application_1469916118318_0003/
16/07/30 22:03:31 INFO tools.DistCp: DistCp job-id: job_1469916118318_0003
16/07/30 22:03:31 INFO mapreduce.Job: Running job: job_1469916118318_0003
16/07/30 22:03:43 INFO mapreduce.Job: Job job_1469916118318_0003 running in uber mode : false
16/07/30 22:03:43 INFO mapreduce.Job: map 0% reduce 0%
16/07/30 22:03:52 INFO mapreduce.Job: map 100% reduce 0%
16/07/30 22:03:53 INFO mapreduce.Job: Job job_1469916118318_0003 completed successfully
16/07/30 22:03:53 INFO mapreduce.Job: Counters: 32
File System Counters
FILE: Number of bytes read=0
FILE: Number of bytes written=142927
FILE: Number of read operations=0
FILE: Number of large read operations=0
FILE: Number of write operations=0
HDFS: Number of bytes read=346
HDFS: Number of bytes written=45
HDFS: Number of read operations=12
HDFS: Number of large read operations=0
HDFS: Number of write operations=2
Job Counters
Launched map tasks=1
Other local map tasks=1
Total time spent by all maps in occupied slots (ms)=14324
Total time spent by all reduces in occupied slots (ms)=0
Total time spent by all map tasks (ms)=7162
Total vcore-seconds taken by all map tasks=7162
Total megabyte-seconds taken by all map tasks=7333888
Map-Reduce Framework
Map input records=1
Map output records=1
Input split bytes=118
Spilled Records=0
Failed Shuffles=0
Merged Map outputs=0
GC time elapsed (ms)=77
CPU time spent (ms)=1210
Physical memory (bytes) snapshot=169885696
Virtual memory (bytes) snapshot=2337554432
Total committed heap usage (bytes)=66584576
File Input Format Counters
Bytes Read=228
File Output Format Counters
Bytes Written=45
org.apache.hadoop.tools.mapred.CopyMapper$Counter
BYTESSKIPPED=0
SKIP=1
Note – hwx-1.hwx.com is the Active Namenode of Cluster 1.
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Please comment if you have any feedback/questions/suggestions. Happy Hadooping!! 🙂
References:
https://community.hortonworks.com/articles/18686/kerberos-cross-realm-trust-for-distcp.html
