[Freeipa-users] replica DS failure deadlock

Ludwig Krispenz lkrispen at redhat.com
Wed Oct 19 15:02:28 UTC 2016


On 10/19/2016 03:48 PM, Andrew E. Bruno wrote:
> On Wed, Oct 19, 2016 at 10:13:26AM +0200, Ludwig Krispenz wrote:
>> On 10/18/2016 08:52 PM, Andrew E. Bruno wrote:
>>> We had one of our replicas fail today with the following errors:
>>>
>>>
>>> [18/Oct/2016:13:40:47 -0400] agmt="cn=meTosrv-m14-32.cbls.ccr.buffalo.edu" (srv-m14-32:389) - Can't locate CSN 58065ef3000100030000 in the changelog (DB rc=-30988). If replication stops, the consumer may need to be reinitialized.
>>> [18/Oct/2016:13:43:07 -0400] NSMMReplicationPlugin - changelog program - _cl5WriteOperationTxn: retry (49) the transaction (csn=58065f74000500040000) failed (rc=-30993 (BDB0068 DB_LOCK_DEADLOCK: Locker killed to resolve a deadlock))
>>> [18/Oct/2016:13:43:07 -0400] NSMMReplicationPlugin - changelog program - _cl5WriteOperationTxn: failed to write entry with csn (58065f74000500040000); db error - -30993 BDB0068 DB_LOCK_DEADLOCK: Locker killed to resolve a deadlock
>>> [18/Oct/2016:13:43:07 -0400] NSMMReplicationPlugin - write_changelog_and_ruv: can't add a change for uid=janedoe,cn=users,cn=accounts,dc=cbls,dc=ccr,dc=buffalo,dc=edu (uniqid: 939bca48-2ced11e5-ac0b8f7e-e0b1a377, optype: 64) to changelog csn 58065f74000500040000
>>> [18/Oct/2016:13:43:07 -0400] - SLAPI_PLUGIN_BE_TXN_POST_MODRDN_FN plugin returned error but did not set SLAPI_RESULT_CODE
>>> [18/Oct/2016:13:43:07 -0400] NSMMReplicationPlugin - process_postop: Failed to apply update (58065f74000500040000) error (1).  Aborting replication session(conn=1314106 op=1688559)
>>> [18/Oct/2016:13:43:12 -0400] - cos_cache_change_notify: modified entry is NULL--updating cache just in case
>>> [18/Oct/2016:13:43:12 -0400] - Skipping CoS Definition cn=Password Policy,cn=accounts,dc=cbls,dc=ccr,dc=buffalo,dc=edu--no CoS Templates found, which should be added before the CoS Definition.
>>> [18/Oct/2016:13:43:20 -0400] - Operation error fetching Null DN (4a729f9a-955a11e6-aaffa516-e778e883), error -30993.
>>> [18/Oct/2016:13:43:20 -0400] - dn2entry_ext: Failed to get id for changenumber=30856302,cn=changelog from entryrdn index (-30993)
>>> [18/Oct/2016:13:43:20 -0400] - Operation error fetching changenumber=30856302,cn=changelog (null), error -30993.
>>> [18/Oct/2016:13:43:20 -0400] DSRetroclPlugin - replog: an error occured while adding change number 30856302, dn = changenumber=30856302,cn=changelog: Operations error.
>>> [18/Oct/2016:13:43:20 -0400] retrocl-plugin - retrocl_postob: operation failure [1]
>>> [18/Oct/2016:13:43:20 -0400] NSMMReplicationPlugin - process_postop: Failed to apply update (58065f9f000000600000) error (1).  Aborting replication session(conn=1901274 op=5)
>>> [18/Oct/2016:13:43:24 -0400] - ldbm_back_seq deadlock retry BAD 1601, err=0 BDB0062 Successful return: 0
>>> [18/Oct/2016:13:43:25 -0400] NSMMReplicationPlugin - changelog program - _cl5WriteOperationTxn: retry (49) the transaction (csn=58065f7c000a00040000) failed (rc=-30993 (BDB0068 DB_LOCK_DEADLOCK: Locker killed to resolve a deadlock))
>>> [18/Oct/2016:13:43:25 -0400] NSMMReplicationPlugin - changelog program - _cl5WriteOperationTxn: failed to write entry with csn (58065f7c000a00040000); db error - -30993 BDB0068 DB_LOCK_DEADLOCK: Locker killed to resolve a deadlock
>>> [18/Oct/2016:13:43:25 -0400] NSMMReplicationPlugin - write_changelog_and_ruv: can't add a change for uid=janedoe,cn=users,cn=accounts,dc=cbls,dc=ccr,dc=buffalo,dc=edu (uniqid: 4080421a-2d0211e5-ac0b8f7e-e0b1a377, optype: 64) to changelog csn 58065f7c000a00040000
>>>
>>>
>>> ns-slapd was hung so we restarted and now it's stuck and won't come back up. It
>>> hangs up here:
>>>
>>> [18/Oct/2016:14:12:31 -0400] - Skipping CoS Definition cn=Password Policy,cn=accounts,dc=cbls,dc=ccr,dc=buffalo,dc=edu--no CoS Templates found, which should be added before the CoS Definition.
>>> [18/Oct/2016:14:12:31 -0400] NSMMReplicationPlugin - changelog program - _cl5NewDBFile: PR_DeleteSemaphore: /var/lib/dirsrv/slapd-CBLS-CCR-BUFFALO-EDU/cldb/a32992ce-71b811e5-9d33a516-e778e883.sema; NSPR error - -5943
>>> [18/Oct/2016:14:12:32 -0400] NSMMReplicationPlugin - changelog program - _cl5NewDBFile: PR_DeleteSemaphore: /var/lib/dirsrv/slapd-CBLS-CCR-BUFFALO-EDU/cldb/986efe12-71b811e5-9d33a516-e778e883.sema; NSPR error - -5943
>>>
>>>
>>> Tried deleting the semaphore files and restarting but no luck. Attached
>>> is a stacktrace of the stuck ns-slapd process.
>>>
>>> Here's the versions were running:
>>>
>>> ipa-server-4.2.0-15.0.1.el7.centos.19.x86_64
>>> 389-ds-base-1.3.4.0-33.el7_2.x86_64
>>>
>>> FWIW, we were experimenting with the new life-cycle management features,
>>> specifically "preserved" users and deleted the user "janedoe" when this
>>> happened.  From the errors above looks like this host failed to
>>> replicate the change?  Not sure if this is related or not.
>>>
>>> Is it possible to recover the database? Thanks in advance for any pointers.
>> from the stack trace the process is not hanging, it is trying to recover.
>> After a crash/kill  the changelog does not contai a RUV and it is
>> reconstructed by reading all records in the changelog, if this is large it
>> can take some time.
>> If you look at that part of the stack repeatedly,
>>
>> #4  0x00007f4e88daeba5 in cl5DBData2Entry (data=<optimized out>, len=<optimized out>, entry=entry at entry=0x7ffff6598910) at ldap/servers/plugins/replication/cl5_api.c:2342
>>          rc = <optimized out>
>>          version = <optimized out>
>>          pos = 0x7f4e9839d091 ""
>>          strCSN = 0x0
>>          op = 0x7ffff6598980
>>          add_mods = 0x7f4e983a5e80
>>          rawDN = 0x7f4e98396e20 "fqdn=cpn-k08-29-02.cbls.ccr.buffalo.edu,cn=computers,cn=accounts,dc=cbls,dc=ccr,dc=buffalo,dc=edu"
>>          s = "\300\037>\230N\177\000\000@\210Y\366\377\177\000\000@\210Y\366\377"
>> #5  0x00007f4e88daf5d6 in _cl5GetNextEntry (entry=entry at entry=0x7ffff6598910, iterator=0x7f4e983a5e80) at ldap/servers/plugins/replication/cl5_api.c:5291
>>          rc = 0
>>          it = 0x7f4e983a5e80
>>          key = {data = 0x0, size = 21, ulen = 0, dlen = 0, doff = 0, app_data = 0x0, flags = 16}
>>          data = {data = 0x7f4e9839cff0, size = 335, ulen = 0, dlen = 0, doff = 0, app_data = 0x0, flags = 16}
>> #6  0x00007f4e88dafb34 in _cl5ConstructRUV (purge=1, obj=0x7f4e983e1fc0, replGen=0x7ffff6598910 "\200\211Y\366\377\177") at ldap/servers/plugins/replication/cl5_api.c:4306
>>
>>
>> you should see some progress in which entry is handled
>>
> Ludwig, thanks very much for the help. As you pointed out just needed to let it
> finish.  ns-slapd eventually came back up once it finished reading the
> changelog. Still seeing some errors related to the NSMMReplicationPlugin failed
> to apply update and from the managed-entries-plugin. Can these safely be
> ignored or are they indicative of a more serious problem?
>
> [19/Oct/2016:09:28:46 -0400] - Operation error fetching Null DN (e73b48a4-95ff11e6-8bc7a516-e778e883), error -30993.
> [19/Oct/2016:09:28:46 -0400] - dn2entry_ext: Failed to get id for changenumber=30856335,cn=changelog from entryrdn index (-30993)
> [19/Oct/2016:09:28:46 -0400] - Operation error fetching changenumber=30856335,cn=changelog (null), error -30993.
> [19/Oct/2016:09:28:46 -0400] DSRetroclPlugin - replog: an error occured while adding change number 30856335, dn = changenumber=30856335,cn=changelog: Operations error.
> [19/Oct/2016:09:28:46 -0400] retrocl-plugin - retrocl_postob: operation failure [1]
> [19/Oct/2016:09:28:46 -0400] NSMMReplicationPlugin - process_postop: Failed to apply update (5806acf7000000600000) error (1).  Aborting replication session(conn=9 op=28)
> [19/Oct/2016:09:28:54 -0400] - Operation error fetching Null DN (e73b48a7-95ff11e6-8bc7a516-e778e883), error -30993.
> [19/Oct/2016:09:28:59 -0400] - dn2entry_ext: Failed to get id for changenumber=30856337,cn=changelog from entryrdn index (-30993)
> [19/Oct/2016:09:29:17 -0400] - Operation error fetching changenumber=30856337,cn=changelog (null), error -30993.
> [19/Oct/2016:09:29:17 -0400] DSRetroclPlugin - replog: an error occured while adding change number 30856337, dn = changenumber=30856337,cn=changelog: Operations error.
> [19/Oct/2016:09:29:17 -0400] retrocl-plugin - retrocl_postob: operation failure [1]
> [19/Oct/2016:09:29:17 -0400] NSMMReplicationPlugin - process_postop: Failed to apply update (5806acf7000000600000) error (1).  Aborting replication session(conn=15 op=5)
> [19/Oct/2016:09:29:20 -0400] - Retry count exceeded in delete
> [19/Oct/2016:09:29:20 -0400] DSRetroclPlugin - delete_changerecord: could not delete change record 30712389 (rc: 51)
> [19/Oct/2016:09:29:28 -0400] - Operation error fetching Null DN (0afe8e82-960011e6-8bc7a516-e778e883), error -30993.
> [19/Oct/2016:09:29:28 -0400] - dn2entry_ext: Failed to get id for changenumber=30856351,cn=changelog from entryrdn index (-30993)
> [19/Oct/2016:09:29:28 -0400] - Operation error fetching changenumber=30856351,cn=changelog (null), error -30993.
> [19/Oct/2016:09:29:28 -0400] DSRetroclPlugin - replog: an error occured while adding change number 30856351, dn = changenumber=30856351,cn=changelog: Operations error.
> [19/Oct/2016:09:29:28 -0400] retrocl-plugin - retrocl_postob: operation failure [1]
> [19/Oct/2016:09:29:28 -0400] NSMMReplicationPlugin - process_postop: Failed to apply update (5806acf7000000600000) error (1).  Aborting replication session(conn=25 op=5)
> [19/Oct/2016:09:29:31 -0400] - Retry count exceeded in delete
> [19/Oct/2016:09:29:31 -0400] DSRetroclPlugin - delete_changerecord: could not delete change record 30712865 (rc: 51)
> [19/Oct/2016:09:29:39 -0400] - Operation error fetching Null DN (0afe8e90-960011e6-8bc7a516-e778e883), error -30993.
> [19/Oct/2016:09:29:39 -0400] - dn2entry_ext: Failed to get id for changenumber=30856364,cn=changelog from entryrdn index (-30993)
> [19/Oct/2016:09:29:39 -0400] - Operation error fetching changenumber=30856364,cn=changelog (null), error -30993.
> [19/Oct/2016:09:29:39 -0400] DSRetroclPlugin - replog: an error occured while adding change number 30856364, dn = changenumber=30856364,cn=changelog: Operations error.
> [19/Oct/2016:09:29:39 -0400] retrocl-plugin - retrocl_postob: operation failure [1]
> [19/Oct/2016:09:29:39 -0400] NSMMReplicationPlugin - process_postop: Failed to apply update (5806acf7000000600000) error (1).  Aborting replication session(conn=35 op=5)
> [19/Oct/2016:09:29:42 -0400] - Retry count exceeded in delete
> [19/Oct/2016:09:29:42 -0400] DSRetroclPlugin - delete_changerecord: could not delete change record 30713364 (rc: 51)
> [19/Oct/2016:09:29:42 -0400] - Operation error fetching Null DN (0afe8ea0-960011e6-8bc7a516-e778e883), error -30993.
> [19/Oct/2016:09:29:42 -0400] - dn2entry_ext: Failed to get id for changenumber=30856379,cn=changelog from entryrdn index (-30993)
> [19/Oct/2016:09:29:42 -0400] - Operation error fetching changenumber=30856379,cn=changelog (null), error -30993.
> [19/Oct/2016:09:29:42 -0400] DSRetroclPlugin - replog: an error occured while adding change number 30856379, dn = changenumber=30856379,cn=changelog: Operations error.
> [19/Oct/2016:09:29:42 -0400] retrocl-plugin - retrocl_postob: operation failure [1]
> [19/Oct/2016:09:29:42 -0400] NSMMReplicationPlugin - process_postop: Failed to apply update (5806acf7000000600000) error (1).  Aborting replication session(conn=36 op=5)
> [19/Oct/2016:09:29:50 -0400] - Operation error fetching Null DN (0afe8ea2-960011e6-8bc7a516-e778e883), error -30993.
> [19/Oct/2016:09:29:50 -0400] - dn2entry_ext: Failed to get id for changenumber=30856380,cn=changelog from entryrdn index (-30993)
> [19/Oct/2016:09:29:50 -0400] - Operation error fetching changenumber=30856380,cn=changelog (null), error -30993.
> [19/Oct/2016:09:29:50 -0400] DSRetroclPlugin - replog: an error occured while adding change number 30856380, dn = changenumber=30856380,cn=changelog: Operations error.
> [19/Oct/2016:09:29:50 -0400] retrocl-plugin - retrocl_postob: operation failure [1]
this doesn't look good. There could be cancelled ops which would be 
repeated, but the failing repl op is always with the same csn: 
5806acf7000000600000
so it seems incoming replication is stuck.
you could try to find out which entry is affected (grep for the csn in 
the access log and look at the operation) and what kind of modification 
it is to check what could be going wrong.
> ...
> [19/Oct/2016:09:30:06 -0400] managed-entries-plugin - mep_mod_post_op: Unable to find config for origin entry "uid=janedoe,cn=deleted users,cn=accounts,cn=provisioning,dc=cbls,dc=ccr,dc=buffalo,dc=edu".
> [19/Oct/2016:09:30:06 -0400] managed-entries-plugin - mep_mod_post_op: Unable to find config for origin entry "uid=janedoe,cn=deleted users,cn=accounts,cn=provisioning,dc=cbls,dc=ccr,dc=buffalo,dc=edu".
>
>
>
>
>

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