--On Thursday, August 01, 2019 4:16 PM +0000 quanah@openldap.org wrote:

Full_Name: Quanah Gibson-Mount Version: 2.4.47 OS: N/A URL: ftp://ftp.openldap.org/incoming/ Submission from: (NULL) (47.208.128.44)

In investigating why a particular consumer went into REFRESH mode, I find that this was triggered by one of its providers currently parsing a sessionlog. Sessionlog parsing should *not* cause a consumer of that server to fall back to REFRESH.

Some notes on this specific environment and situation.

This is a 4-way MMR setup. Via the use of a load balancer, only iam-ed-ldp-p01 recieves write operations. Thus there should never be any REFRESHes occurring anywhere, so the fact that there is is already problematic.

Servers are p01, p02, p03 (all in the same data center) and b01 (offsite DR system).

At the time this issue hit:

p01 was upgraded to a new release of OpenLDAP @ 21:26:48, thus we see: Jul 30 21:25:17 iam-ed-ldp-p01 slapd[30495]: slapd shutdown: waiting for 0 operations/tasks to finish Jul 30 21:26:48 iam-ed-ldp-p01 slapd[20978]: @(#) $OpenLDAP: slapd 2.4.47 (Mar 22 2019 09:12:20) $#012#011build@rhel7build.rb.symas.net:/home/build/sold-2.4.47.3/redhat7-x86_64/build/openldap.x86_64/servers/slapd Jul 30 21:26:48 iam-ed-ldp-p01 slapd[20979]: slapd starting Jul 30 21:26:48 iam-ed-ldp-p01 slapd[20979]: do_syncrep2: rid=002 LDAP_RES_INTERMEDIATE - REFRESH_DELETE Jul 30 21:26:48 iam-ed-ldp-p01 slapd[20979]: do_syncrep2: rid=001 LDAP_RES_SEARCH_RESULT Jul 30 21:26:48 iam-ed-ldp-p01 slapd[20979]: do_syncrep2: rid=001 delta-sync lost sync, switching to REFRESH Jul 30 21:26:48 iam-ed-ldp-p01 slapd[20979]: do_syncrep2: rid=001 (4096) Content Sync Refresh Required Jul 30 21:26:48 iam-ed-ldp-p01 slapd[20979]: do_syncrep2: rid=003 LDAP_RES_INTERMEDIATE - REFRESH_DELETE

p03 was operating w/o issue. Interstingly enough, when it was restarted for the software update @ 21:37:16, it got an error (53) talking to p02 instead of an error (4096) like p01 did. This is likely because p02 was restarted for its software update @ 21:32:19, which wiped out its sessionlog.

p02 had started doing session log parsing @ 21:26:17 with Jul 30 21:26:17 iam-ed-ldp-p02 slapd[3750]: conn=18205759 op=1 SEARCH RESULT tag=101 err=4096 duration=18.462ms nentries=0 text=sync cookie is stale

We see the connection to p02 from p01 with a similar issue when it starts up: Jul 30 21:26:48 iam-ed-ldp-p02 slapd[3750]: conn=18205790 op=1 SRCH base="cn=accesslog" scope=2 deref=0 filter="(&(objectClass=auditWriteObject)(reqResult=0))" Jul 30 21:26:48 iam-ed-ldp-p02 slapd[3750]: conn=18205790 op=1 SRCH attr=reqDN reqType reqMod reqNewRDN reqDeleteOldRDN reqNewSuperior entryCSN Jul 30 21:26:48 iam-ed-ldp-p02 slapd[3750]: conn=18205790 op=1 SEARCH RESULT tag=101 err=4096 duration=0.431ms nentries=0 text=sync cookie is stale

b01 had its software update @ 21:21:25

Generally it seems like restarting/wiping the sessionlog made things incredibly bad across the cluster.

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Quanah Gibson-Mount Product Architect Symas Corporation Packaged, certified, and supported LDAP solutions powered by OpenLDAP: http://www.symas.com