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? > > 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" >> $OCF_RESKEY_config > > fi > > Sounds good. > > > Don't know if it makes sense to remove it on stop. > > I think it doesn't make sense to remove it, > because rep_mode.conf becomes empty on stop. > The only problem here if admin changes temp_dir parameter but doesn't delete records from postgres.conf. We could end up with several include records then or with records pointing to the non existing files. > >> > 3. I don't really like this part of pgsql_real_monitor: > >> > > >> > 775 if ! is_replication; then > >> > 776 OCF_RESKEY_monitor_sql=`escape_string > > >> > "$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? > > >> > >> > >> > 5. It also requires some changes in terms of a proper English but we > can > >> > go > >> > through it later. > >> > >> I hope your help. > > > > > > Will do. > > > >> > >> > >> > > >> > And yet again thanks for a brilliant work. > >> > > >> Thank you for the compliment. > >> > >> > Florian, Dejan how would you like to merge a patch when we are ready? > >> > The > >> > patch will be rather big one and AFAIK you have some policy on the > >> > amount of > >> > changes for one patch. > > > 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/ > -- Serge Dubrouski.
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