Re: AW: AW: AW: AW: AW: AW: AW: broken backup trail in case of quickly patroni switchback and forth
"Zwettler Markus (OIZ)" wrote on 2019/11/08 11:54:14 AM: > > (please don't top post, makes the replies hard to follow) > > > patronictl switchover > > > follow the prompts > > > there is also a /switchover API endpoint you can use. > > > Brad > > I wondered about your "patronictl switchover + systemd" hint. How > would you do ("gate") this combination? Change whatever process you are using today to shut things down to call the patroni switchover first, check error codes, etc.
AW: AW: AW: AW: AW: AW: AW: broken backup trail in case of quickly patroni switchback and forth
? "Zwettler Markus (OIZ)" mailto:markus.zwett...@zuerich.ch>> wrote on 2019/11/08 11:27:00 AM: >> From: "Zwettler Markus (OIZ)" >> mailto:markus.zwett...@zuerich.ch>> >> To: Brad Nicholson mailto:br...@ca.ibm.com>> >> Cc: Adrian Klaver >> mailto:adrian.kla...@aklaver.com>>, "pgsql- >> gene...@lists.postgresql.org<mailto:gene...@lists.postgresql.org>" >> mailto:pgsql-general@lists.postgresql.org>> >> Date: 2019/11/08 11:27 AM >>> Subject: [EXTERNAL] AW: AW: AW: AW: AW: AW: broken backup trail >> in case of quickly patroni switchback and forth >> >> How exactly? Please clarify. > (please don't top post, makes the replies hard to follow) > patronictl switchover > follow the prompts > there is also a /switchover API endpoint you can use. > Brad I wondered about your "patronictl switchover + systemd" hint. How would you do ("gate") this combination? Markus
Re: AW: AW: AW: AW: AW: AW: broken backup trail in case of quickly patroni switchback and forth
"Zwettler Markus (OIZ)" wrote on 2019/11/08 11:27:00 AM: > From: "Zwettler Markus (OIZ)" > To: Brad Nicholson > Cc: Adrian Klaver , "pgsql- > gene...@lists.postgresql.org" > Date: 2019/11/08 11:27 AM > Subject: [EXTERNAL] AW: AW: AW: AW: AW: AW: broken backup trail > in case of quickly patroni switchback and forth > > How exactly? Please clarify. (please don't top post, makes the replies hard to follow) patronictl switchover follow the prompts there is also a /switchover API endpoint you can use. Brad
AW: AW: AW: AW: AW: AW: broken backup trail in case of quickly patroni switchback and forth
How exactly? Please clarify. "Zwettler Markus (OIZ)" mailto:markus.zwett...@zuerich.ch>> wrote on 2019/11/08 11:02:49 AM: > From: "Zwettler Markus (OIZ)" > mailto:markus.zwett...@zuerich.ch>> > To: Brad Nicholson mailto:br...@ca.ibm.com>> > Cc: Adrian Klaver > mailto:adrian.kla...@aklaver.com>>, "pgsql- > gene...@lists.postgresql.org<mailto:gene...@lists.postgresql.org>" > mailto:pgsql-general@lists.postgresql.org>> > Date: 2019/11/08 11:02 AM > Subject: [EXTERNAL] AW: AW: AW: AW: AW: broken backup trail in > case of quickly patroni switchback and forth > > Let me clarify: "But, it might start killing processes after a > certain period if a _fast_ shutdown after SIGTERM didn't happen". > > I am talking about stopping the Patroni master process with a systemd scipt. Use the switchover functionality in Patroni first, and gate youur shutdown via systemd on the success of that operation. Brad.
Re: AW: AW: AW: AW: AW: broken backup trail in case of quickly patroni switchback and forth
"Zwettler Markus (OIZ)" wrote on 2019/11/08 11:02:49 AM: > From: "Zwettler Markus (OIZ)" > To: Brad Nicholson > Cc: Adrian Klaver , "pgsql- > gene...@lists.postgresql.org" > Date: 2019/11/08 11:02 AM > Subject: [EXTERNAL] AW: AW: AW: AW: AW: broken backup trail in > case of quickly patroni switchback and forth > > Let me clarify: "But, it might start killing processes after a > certain period if a _fast_ shutdown after SIGTERM didn't happen". > > I am talking about stopping the Patroni master process with a systemd scipt. Use the switchover functionality in Patroni first, and gate youur shutdown via systemd on the success of that operation. Brad.
AW: AW: AW: AW: AW: broken backup trail in case of quickly patroni switchback and forth
Let me clarify: "But, it might start killing processes after a certain period if a _fast_ shutdown after SIGTERM didn't happen". I am talking about stopping the Patroni master process with a systemd scipt. Von: Brad Nicholson Gesendet: Freitag, 8. November 2019 15:58 An: Zwettler Markus (OIZ) Cc: Adrian Klaver ; pgsql-general@lists.postgresql.org Betreff: Re: AW: AW: AW: AW: broken backup trail in case of quickly patroni switchback and forth "Zwettler Markus (OIZ)" mailto:markus.zwett...@zuerich.ch>> wrote on 2019/11/08 07:51:33 AM: > From: "Zwettler Markus (OIZ)" > mailto:markus.zwett...@zuerich.ch>> > To: Brad Nicholson mailto:br...@ca.ibm.com>> > Cc: Adrian Klaver > mailto:adrian.kla...@aklaver.com>>, "pgsql- > gene...@lists.postgresql.org<mailto:gene...@lists.postgresql.org>" > mailto:pgsql-general@lists.postgresql.org>> > Date: 2019/11/08 07:51 AM > Subject: [EXTERNAL] AW: AW: AW: AW: broken backup trail in case of > quickly patroni switchback and forth > > It depends. It is a switchover if Patroni could to a clean shutdown. > But, it might start killing processes after a certain period if a > normal shutdown after SIGTERM didn't happen. This would not be a > switchover anymore. In other words there is no guarantee for a > "clean" switchover. This might be the reason why the Patroni guys > are always talking about failover only. If it can't do a clean shutdown, that points to something wrong with Postgres itself. Why doesn't a fast shutdown work for you in those cases? > It's not a Patroni issue but it's triggered by Patroni as it will do > "some kind of switchover" on a regular shutdown. Sure, but you should be looking at why Postgres can't cleanly shutdown. How are you telling Patroni to switchover? Are you using the Patroni switchover command via patronictl or the API, or sending a signal to the Patroni process? I think the explicit switchover command will not behave this way. It will return you a 503 if it can't switchover and not change the primary (that is something you can confirm with the Patroni developers). Brad.
Re: AW: AW: AW: AW: broken backup trail in case of quickly patroni switchback and forth
"Zwettler Markus (OIZ)" wrote on 2019/11/08 07:51:33 AM: > From: "Zwettler Markus (OIZ)" > To: Brad Nicholson > Cc: Adrian Klaver , "pgsql- > gene...@lists.postgresql.org" > Date: 2019/11/08 07:51 AM > Subject: [EXTERNAL] AW: AW: AW: AW: broken backup trail in case of > quickly patroni switchback and forth > > It depends. It is a switchover if Patroni could to a clean shutdown. > But, it might start killing processes after a certain period if a > normal shutdown after SIGTERM didn't happen. This would not be a > switchover anymore. In other words there is no guarantee for a > "clean" switchover. This might be the reason why the Patroni guys > are always talking about failover only. If it can't do a clean shutdown, that points to something wrong with Postgres itself. Why doesn't a fast shutdown work for you in those cases? > It's not a Patroni issue but it's triggered by Patroni as it will do > "some kind of switchover" on a regular shutdown. Sure, but you should be looking at why Postgres can't cleanly shutdown. How are you telling Patroni to switchover? Are you using the Patroni switchover command via patronictl or the API, or sending a signal to the Patroni process? I think the explicit switchover command will not behave this way. It will return you a 503 if it can't switchover and not change the primary (that is something you can confirm with the Patroni developers). Brad.
AW: AW: AW: AW: broken backup trail in case of quickly patroni switchback and forth
It depends. It is a switchover if Patroni could to a clean shutdown. But, it might start killing processes after a certain period if a normal shutdown after SIGTERM didn't happen. This would not be a switchover anymore. In other words there is no guarantee for a "clean" switchover. This might be the reason why the Patroni guys are always talking about failover only. It's not a Patroni issue but it's triggered by Patroni as it will do "some kind of switchover" on a regular shutdown. "Zwettler Markus (OIZ)" mailto:markus.zwett...@zuerich.ch>> wrote on 2019/11/07 11:32:42 AM: > From: "Zwettler Markus (OIZ)" > mailto:markus.zwett...@zuerich.ch>> > To: Adrian Klaver > mailto:adrian.kla...@aklaver.com>>, "pgsql- > gene...@lists.postgresql.org<mailto:gene...@lists.postgresql.org>" > mailto:pgsql-general@lists.postgresql.org>> > Date: 2019/11/07 11:33 AM > Subject: [EXTERNAL] AW: AW: AW: broken backup trail in case of > quickly patroni switchback and forth > > 3) > Patroni does only failovers. Also in case of regular shutdown of the > primary. A failover is a promote of the standby + automatic > reinstate (pg_rewind or pg_basebackup) of the former primary. This is not accurate. Patroni does controlled switchovers as well as failovers. Controlled switchover issues a fast shutdown to Postgres, hard ones issue an immediate shutdown. From this point, it's how Postgres responds to those that matter. Fast shutdown will attempt to ensure the wal stream is transmitted to the replica and the wal files are archived. Immediate shutdown will not do any of this. This issue explains more about when Patroni may choose an immediate shutdown (it might not be totally accurate anymore as it's a year old). https://github.com/zalando/patroni/issues/837#issuecomment-433686687 I agree with the Patroni folks that this is not a Patroni issue, but simply how Postgres responds to the required shutdown types.
Re: AW: AW: AW: broken backup trail in case of quickly patroni switchback and forth
"Zwettler Markus (OIZ)" wrote on 2019/11/07 11:32:42 AM: > From: "Zwettler Markus (OIZ)" > To: Adrian Klaver , "pgsql- > gene...@lists.postgresql.org" > Date: 2019/11/07 11:33 AM > Subject: [EXTERNAL] AW: AW: AW: broken backup trail in case of > quickly patroni switchback and forth > > 3) > Patroni does only failovers. Also in case of regular shutdown of the > primary. A failover is a promote of the standby + automatic > reinstate (pg_rewind or pg_basebackup) of the former primary. This is not accurate. Patroni does controlled switchovers as well as failovers. Controlled switchover issues a fast shutdown to Postgres, hard ones issue an immediate shutdown. From this point, it's how Postgres responds to those that matter. Fast shutdown will attempt to ensure the wal stream is transmitted to the replica and the wal files are archived. Immediate shutdown will not do any of this. This issue explains more about when Patroni may choose an immediate shutdown (it might not be totally accurate anymore as it's a year old). https://github.com/zalando/patroni/issues/837#issuecomment-433686687 I agree with the Patroni folks that this is not a Patroni issue, but simply how Postgres responds to the required shutdown types.
AW: AW: AW: broken backup trail in case of quickly patroni switchback and forth
3) Patroni does only failovers. Also in case of regular shutdown of the primary. A failover is a promote of the standby + automatic reinstate (pg_rewind or pg_basebackup) of the former primary. Time: role site 1 - role site 2 12:00h: primary - standby => Some clients commited some transactions; Primary stopped => Failover to standby 12:05h: standby - primary => Some clients connected + commited some transactions; Primary stopped => Failover to standby 12:10h: primary - standby Patroni.yml) $ cat pcl_l702.yml scope: pcl_l702 name: pcl_l702@tstm49003 namespace: /patroni/ log: level: DEBUG dir: /opt/app/patroni/etc/log/ file_num: 10 file_size: 104857600 restapi: listen: tstm49003.tstglobal.tst.loc:8010 connect_address: tstm49003.tstglobal.tst.loc:8010 etcd: hosts: etcdlab01.tstglobal.tst.loc:2379,etcdlab02.tstglobal.tst.loc:2379,etcdlab03.tstglobal.tst.loc:2379,etcdlab04.tstglobal.tst.loc:2379,etcdlab05.tstglobal.tst.loc:2379 username: patroni password: censored bootstrap: dcs: ttl: 30 loop_wait: 10 retry_timeout: 10 maximum_lag_on_failover: 1048576 master_start_timeout: 300 synchronous_mode: true postgresql: use_pg_rewind: true use_slots: true # NO BOOTSTRAPPING USED method: do_not_bootstrap do_not_bootstrap: command: /bin/false postgresql: authentication: replication: username: repadmin password: censored superuser: username: patroni password: censored callbacks: on_reload: /opt/app/patroni/etc/callback_patroni.sh on_restart: /opt/app/patroni/etc/callback_patroni.sh on_role_change: /opt/app/patroni/etc/callback_patroni.sh on_start: /opt/app/patroni/etc/callback_patroni.sh on_stop: /opt/app/patroni/etc/callback_patroni.sh connect_address: tstm49003.tstglobal.tst.loc:5436 database: pcl_l702 data_dir: /pgdata/pcl_l702 bin_dir: /usr/pgsql-9.6/bin listen: localhost,tstm49003.tstglobal.tst.loc,pcl_l702.tstglobal.tst.loc:5436 pgpass: /home/postgres/.pgpass_patroni recovery_conf: restore_command: cp /pgxlog_archive/pcl_l702/%f %p parameters: hot_standby_feedback: on wal_keep_segments: 64 use_pg_rewind: true watchdog: mode: automatic device: /dev/watchdog safety_margin: 5 tags: nofailover: false noloadbalance: false clonefrom: false nosync: false -Ursprüngliche Nachricht- Von: Adrian Klaver Gesendet: Donnerstag, 7. November 2019 17:06 An: Zwettler Markus (OIZ) ; pgsql-general@lists.postgresql.org Betreff: Re: AW: AW: broken backup trail in case of quickly patroni switchback and forth On 11/7/19 7:47 AM, Zwettler Markus (OIZ) wrote: I am heading out the door so I will not have time to look at below until later. For those that get a chance before then, it would be nice to have the Patroni conf file information also. The Patroni information may answer the question, but it case it does not what actually is failover in 3) below? > 1) 9.6 > > > > 2) > $ cat postgresql.conf > # Do not edit this file manually! > # It will be overwritten by Patroni! > include 'postgresql.base.conf' > > cluster_name = 'pcl_l702' > hot_standby = 'on' > hot_standby_feedback = 'True' > listen_addresses = > 'localhost,tstm49003.tstglobal.tst.loc,pcl_l702.tstglobal.tst.loc' > max_connections = '100' > max_locks_per_transaction = '64' > max_prepared_transactions = '0' > max_replication_slots = '10' > max_wal_senders = '10' > max_worker_processes = '8' > port = '5436' > track_commit_timestamp = 'off' > wal_keep_segments = '8' > wal_level = 'replica' > wal_log_hints = 'on' > hba_file = '/pgdata/pcl_l702/pg_hba.conf' > ident_file = '/pgdata/pcl_l702/pg_ident.conf' > $ > $ > $ > $ cat postgresql.base.conf > datestyle = 'iso, mdy' > default_text_search_config = 'pg_catalog.english' > dynamic_shared_memory_type = posix > lc_messages = 'en_US.UTF-8' > lc_monetary = 'de_CH.UTF-8' > lc_numeric = 'de_CH.UTF-8' > lc_time = 'de_CH.UTF-8' > logging_collector = on > log_directory = 'pg_log' > log_rotation_age = 1d > log_rotation_size = 0 > log_timezone = 'Europe/Vaduz' > log_truncate_on_rotation = on > max_connections = 100 > timezone = 'Europe/Vaduz' > archive_command = 'test ! -f /tmp/pg_archive_backup_running_on_pcl_l702* && > rsync --checksum %p /pgxlog_archive/pcl_l702/%f' > archive_mode = on > archive_timeout = 1800 > cluster_name = pcl_l702 > cron.database_name = 'pdb_l72_oiz' > # effective_cache_size > listen_addresses = '*' > log_connectio
Re: AW: AW: broken backup trail in case of quickly patroni switchback and forth
On 11/7/19 7:47 AM, Zwettler Markus (OIZ) wrote: I am heading out the door so I will not have time to look at below until later. For those that get a chance before then, it would be nice to have the Patroni conf file information also. The Patroni information may answer the question, but it case it does not what actually is failover in 3) below? 1) 9.6 2) $ cat postgresql.conf # Do not edit this file manually! # It will be overwritten by Patroni! include 'postgresql.base.conf' cluster_name = 'pcl_l702' hot_standby = 'on' hot_standby_feedback = 'True' listen_addresses = 'localhost,tstm49003.tstglobal.tst.loc,pcl_l702.tstglobal.tst.loc' max_connections = '100' max_locks_per_transaction = '64' max_prepared_transactions = '0' max_replication_slots = '10' max_wal_senders = '10' max_worker_processes = '8' port = '5436' track_commit_timestamp = 'off' wal_keep_segments = '8' wal_level = 'replica' wal_log_hints = 'on' hba_file = '/pgdata/pcl_l702/pg_hba.conf' ident_file = '/pgdata/pcl_l702/pg_ident.conf' $ $ $ $ cat postgresql.base.conf datestyle = 'iso, mdy' default_text_search_config = 'pg_catalog.english' dynamic_shared_memory_type = posix lc_messages = 'en_US.UTF-8' lc_monetary = 'de_CH.UTF-8' lc_numeric = 'de_CH.UTF-8' lc_time = 'de_CH.UTF-8' logging_collector = on log_directory = 'pg_log' log_rotation_age = 1d log_rotation_size = 0 log_timezone = 'Europe/Vaduz' log_truncate_on_rotation = on max_connections = 100 timezone = 'Europe/Vaduz' archive_command = 'test ! -f /tmp/pg_archive_backup_running_on_pcl_l702* && rsync --checksum %p /pgxlog_archive/pcl_l702/%f' archive_mode = on archive_timeout = 1800 cluster_name = pcl_l702 cron.database_name = 'pdb_l72_oiz' # effective_cache_size listen_addresses = '*' log_connections = on log_destination = 'stderr, csvlog' log_disconnections = on log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log' log_line_prefix = '%t : %h=>%u@%d : %p-%c-%v : %e ' log_statement = 'ddl' max_wal_senders = 5 port = 5436 shared_buffers = 512MB shared_preload_libraries = 'auto_explain, pg_stat_statements, pg_cron, pg_statsinfo' wal_buffers = 16MB wal_compression = on wal_level = replica # work_mem 3) 12:00h: primary - standby => Some clients commited some transactions; Failover 12:05h: standby - primary => Some clients connected + commited some transactions; Failover 12:10h: primary - standby On 11/7/19 7:18 AM, Zwettler Markus (OIZ) wrote: I already asked the Patroni folks. They told me this is not related to Patroni but Postgresql. ;-) Hard to say without more information: 1) Postgres version 2) Setup/config info 3) Detail if what happened between 12:00 and 12:10 - Markus On 11/7/19 5:52 AM, Zwettler Markus (OIZ) wrote: we are using Patroni for management of our Postgres standby databases. we take our (wal) backups on the primary side based on intervals and thresholds. our archived wal's are written to a local wal directory first and moved to tape afterwards. we got a case where Patroni switched back and forth sides quickly, e.g.: 12:00h: primary - standby 12:05h: standby - primary 12:10h: primary - standby we realised that we will not have a wal backup of those wal's generated between 12:05h and 12:10h in this scenario. how can we make sure that the whole wal sequence trail will be backuped? any idea? Probably best to ask the Patroni folks: https://github.com/zalando/patroni#community - Markus -- Adrian Klaver adrian.kla...@aklaver.com
AW: AW: broken backup trail in case of quickly patroni switchback and forth
1) 9.6 2) $ cat postgresql.conf # Do not edit this file manually! # It will be overwritten by Patroni! include 'postgresql.base.conf' cluster_name = 'pcl_l702' hot_standby = 'on' hot_standby_feedback = 'True' listen_addresses = 'localhost,tstm49003.tstglobal.tst.loc,pcl_l702.tstglobal.tst.loc' max_connections = '100' max_locks_per_transaction = '64' max_prepared_transactions = '0' max_replication_slots = '10' max_wal_senders = '10' max_worker_processes = '8' port = '5436' track_commit_timestamp = 'off' wal_keep_segments = '8' wal_level = 'replica' wal_log_hints = 'on' hba_file = '/pgdata/pcl_l702/pg_hba.conf' ident_file = '/pgdata/pcl_l702/pg_ident.conf' $ $ $ $ cat postgresql.base.conf datestyle = 'iso, mdy' default_text_search_config = 'pg_catalog.english' dynamic_shared_memory_type = posix lc_messages = 'en_US.UTF-8' lc_monetary = 'de_CH.UTF-8' lc_numeric = 'de_CH.UTF-8' lc_time = 'de_CH.UTF-8' logging_collector = on log_directory = 'pg_log' log_rotation_age = 1d log_rotation_size = 0 log_timezone = 'Europe/Vaduz' log_truncate_on_rotation = on max_connections = 100 timezone = 'Europe/Vaduz' archive_command = 'test ! -f /tmp/pg_archive_backup_running_on_pcl_l702* && rsync --checksum %p /pgxlog_archive/pcl_l702/%f' archive_mode = on archive_timeout = 1800 cluster_name = pcl_l702 cron.database_name = 'pdb_l72_oiz' # effective_cache_size listen_addresses = '*' log_connections = on log_destination = 'stderr, csvlog' log_disconnections = on log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log' log_line_prefix = '%t : %h=>%u@%d : %p-%c-%v : %e ' log_statement = 'ddl' max_wal_senders = 5 port = 5436 shared_buffers = 512MB shared_preload_libraries = 'auto_explain, pg_stat_statements, pg_cron, pg_statsinfo' wal_buffers = 16MB wal_compression = on wal_level = replica # work_mem 3) 12:00h: primary - standby => Some clients commited some transactions; Failover 12:05h: standby - primary => Some clients connected + commited some transactions; Failover 12:10h: primary - standby On 11/7/19 7:18 AM, Zwettler Markus (OIZ) wrote: > I already asked the Patroni folks. They told me this is not related to > Patroni but Postgresql. ;-) Hard to say without more information: 1) Postgres version 2) Setup/config info 3) Detail if what happened between 12:00 and 12:10 > > - Markus > > > > On 11/7/19 5:52 AM, Zwettler Markus (OIZ) wrote: >> we are using Patroni for management of our Postgres standby databases. >> >> we take our (wal) backups on the primary side based on intervals and >> thresholds. >> our archived wal's are written to a local wal directory first and moved to >> tape afterwards. >> >> we got a case where Patroni switched back and forth sides quickly, e.g.: >> 12:00h: primary - standby >> 12:05h: standby - primary >> 12:10h: primary - standby >> >> we realised that we will not have a wal backup of those wal's generated >> between 12:05h and 12:10h in this scenario. >> >> how can we make sure that the whole wal sequence trail will be backuped? any >> idea? > > Probably best to ask the Patroni folks: > > https://github.com/zalando/patroni#community > >> >> - Markus >> >> > > -- Adrian Klaver adrian.kla...@aklaver.com