Hello Serge 2011/12/12 Serge Dubrouski <serge...@gmail.com>: > > > On Thu, Dec 8, 2011 at 10:04 PM, Takatoshi MATSUO <matsuo....@gmail.com> > wrote: >> >> Hello Serge >> >> 2011/12/8 Serge Dubrouski <serge...@gmail.com>: >> > >> > >> > On Mon, Dec 5, 2011 at 9:15 PM, Takatoshi MATSUO <matsuo....@gmail.com> >> > wrote: >> >> >> >> Hello Serge >> >> >> >> Serge Dubrouski <serge...@gmail.com>: >> >> > Hello - >> >> > >> >> > Takatoshi MATSUO did a tremendous job on implementing support for >> >> > streaming >> >> > replication feature in pgsql RA. Also it looks like PostgeSQL 9.1 has >> >> > all >> >> > necessary interfaces to successfully implement Pacemaker's M/S >> >> > concept. >> >> > So >> >> > I think it's time to start discussion on how to merge Takatoshi's >> >> > work >> >> > into >> >> > pgsql RA baseline. Here is the link to Takatoshi's GitHUB if somebody >> >> > wants >> >> > to test his RA: >> >> > >> >> > https://github.com/t-matsuo/ >> >> > >> >> > So far I tested it for backward compatibility in a standard >> >> > non-replication >> >> > mode and also tested M/S model and found no real issues. Though it >> >> > definitely requires some more polishing and testing. >> >> > >> >> > Takatoshi, here are some changes that I want to discuss with you: >> >> > >> >> > 1. Is it possible to add a check for PostgreSQL version and fail with >> >> > OCF_ERR_INSTALLED when one tries to start replication on version less >> >> > than >> >> > 9.1? A simple cat on PG_VERSION with some analysis would probably do. >> >> >> >> I'll add a check. >> >> I added a check. >> >> https://github.com/t-matsuo/resource-agents/commit/3ab7cfdcce118043cd149b348740e50e7a946eb3 >> >> >> >> >> > 2. I think that following lines should be moved from pgsql_start to >> >> > pgsql_validate_all >> >> > >> >> > 535 # Check whether tmpdir is readable by pgdba user >> >> > 536 if ! runasowner "test -r $OCF_RESKEY_tmpdir"; then >> >> > 537 ocf_log err "Directory $OCF_RESKEY_tmpdir is not >> >> > readable >> >> > by >> >> > $OCF_RESKEY_pgdba" >> >> > 538 return $OCF_ERR_PERM >> >> > 539 fi >> >> >> >> Thanks. I think so too. >> >> I'll fix it. >> >> >> >> I fixed it and I deleted a check for tmpdir existence >> because the checking for permittion fills the role. >> >> https://github.com/t-matsuo/resource-agents/commit/82d4939486bcca429e2deb804d7faf756099bb59 >> >> >> > On a second thought I'm not sure why we need that parameter and >> > directory at >> > all. Why not to create rep_mode.conf, PGSQL.lock and xlog.note in >> > $OCF_RESKEY_pgdata ? What problems it can create? >> > >> > One more advantage to do >> > it in $OCF_RESKEY_pgdata is an ability to handle more than PostgreSQL >> > instance on the same server without a need for additional temp >> > directories. >> >> When backup is needed, customers may backup these files and restore it. >> It may cause problems. >> Specially PGSQL.lock causes an error on start. >> >> I think that they should be treated as a separate thing. >> because they are independent from PostgreSQL's data. > > > Ok. Then may be it should default to something like > ${OCF_RESKEY_pgdata}/temp and RA should create it and set the right > ownership and permissions if it doesn't exist? And again may be in this case > we don't need that parameter? >
I agree that RA creates it and sets the right ownership and permissions. But considering backup using tar command, I think it's not better to create it under $OCF_RESKEY_pgdata. According to "Filesystem Hierarchy Standard" it's better to use /var/lib/somewhere. http://www.pathname.com/fhs/pub/fhs-2.3.html#VARLIBVARIABLESTATEINFORMATION, Then I designed using /var/lig/[RA Name] (=/var/lib/pgsql). What do you think? >> >> >> Incidentally I considered to handle more than PostgreSQL instance. >> Initially I added port number to these filenames, but I deleted it >> to simplify filenames. >> >> https://github.com/t-matsuo/resource-agents/commit/b16faf2d797200048dc0fc07a45b6751cf5be190 >> >> >> > Also I think it would be good if RA was able to take care of adding >> > "include >> > $WHATEVER_DIR/rep_mode.conf" in postgresql.conf. It will make the RA >> > self >> > sustainable. In a current situation admin has add that directive >> > manually. >> > RA though can something like this in a start function for replication >> > mode: >> > >> > if ! grep -i "include $WHATEVER_DIR/rep_mode.conf" $OCF_RESKEY_config >> > then >> > echo "include $WHATEVER_DIR/rep_mode.conf" >> $OCF_RESKEY_config >> > fi >> >> Sounds good. >> >> > Don't know if it makes sense to remove it on stop. >> >> I think it doesn't make sense to remove it, >> because rep_mode.conf becomes empty on stop. > > > The only problem here if admin changes temp_dir parameter but doesn't delete > records from postgres.conf. We could end up with several include records > then or with records pointing to the non existing files. Should we consider this situation? If same parameters exist, PostgreSQL uses last parameter. So I will implement it to add several include if temp_dir is changed. >> >> >> > 3. I don't really like this part of pgsql_real_monitor: >> >> > >> >> > 775 if ! is_replication; then >> >> > 776 OCF_RESKEY_monitor_sql=`escape_string > >> >> > "$OCF_RESKEY_monitor_sql"` >> >> > 777 runasowner -q $loglevel "$OCF_RESKEY_psql $psql_options >> >> > -c >> >> > > '$OCF_RESKEY_monitor_sql'" >> >> > 778 rc=$? >> >> > 779 else >> >> > 780 output=`su $OCF_RESKEY_pgdba -c "cd $OCF_RESKEY_pgdata; >> >> > > >> >> > $OCF_RESKEY_psql $psql_options -Atc \"${CHECK_MS_SQL}\""` >> >> > 781 rc=$? >> >> > 782 fi >> >> > >> >> > I think that functional monitor (the one that uses monitor_sql) >> >> > should >> >> > run >> >> > always independently of DB mode since its primary role is to check >> >> > data >> >> > and >> >> > fail if it's not correct or corrupted. In replication mode there >> >> > should >> >> > be >> >> > additional monitoring. Other way it misleads customer on a usage of >> >> > monitor_sql. >> >> >> >> All right. >> >> >> >> Does it need to execute "select now();" if monitor_sql parameter is >> >> empty? >> >> I think it's unnecessary. >> > >> > >> > For a case of an empty parameter you are right and running "select >> > now()" >> > probably unnecessary, Non-empty monitro_sql shall be executed in my >> > opinion. >> > >> >> >> >> >> >> > 4. You already populate several attributes with crm_attribute. Does >> >> > it >> >> > make >> >> > sense to populate a name of a Master node in promote function and use >> >> > it >> >> > later on instead of running crm_mon on each monitor command? >> >> > >> >> >> >> Do you mean that you don't want to use crm_mon in monitor? >> > >> > >> > I prefer to have as few dependencies on external programs as possible. >> >> Agree. >> >> > Using crm_attribute to communicate the name of a master node would be >> > consistent with the rest of the script since you already use it for >> > communicating state of the nodes. If you prefer using crm_mon than you >> > have >> > to add a check that that binary exists on the server. In 99.99% of the >> > case >> > it will but still the check is necessary I think. >> >> I use crm_mon to check for node existence and node online too. >> It is impossible to get it from attribute, so I prefer to using crm_mon. >> >> Do I have to add a check for crm_master, crm_attribute, crm_failcount too? >> > > That's a different interesting topic. What is the reason for doing this? > > my_fail_count=`$CRM_FAILCOUNT -r $OCF_RESOURCE_INSTANCE -N $HOSTNAME -G -Q | > sed "s/INFINITY/1000000/g"` > if [ "$my_fail_count" != "0" ]; then > ocf_log info "I don't start PostgreSQL on post-demote because of my > fail-count=$my_fail_count." > return $OCF_SUCCESS > fi > > Why not to leave pacemaker to do its job on managing failcounts? Because I want to make fail-over faster. At any rate Pacemaker stops it? Regards, Takatoshi MATSUO _______________________________________________________ Linux-HA-Dev: Linux-HA-Dev@lists.linux-ha.org http://lists.linux-ha.org/mailman/listinfo/linux-ha-dev Home Page: http://linux-ha.org/
