PostgreSQL klasterio žurnalų gavimas
Visi PostgreSQL klasterio veikimo žurnalai yra atskirų mazgų faile /var/log/syslog. Ypatingą dėmesį reikėtų skirti patroni ir etcd žurnalams. Šiuos žurnalus galima nuolat rodyti šia komanda (vykdyti kaip root):
Taip pat galite išsamiau peržiūrėti dabartinius šių dviejų paslaugų žurnalus šiomis komandomis:
| journalctl -fu patroni
journalctl -fu etcd
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Paslauga patroni reguliariai nurodys dabartinę mazgo būseną ir tai, ar jis yra LEADER, ar kuris mazgas yra LEADER.
etcd savo ruožtu gali pateikti informacijos apie klasterio būseną.
Pavyzdys
Štai lyderio mazgo žurnalo pavyzdys:
| patroni[1028]: 2023-02-24 17:08:41,198 INFO: no action. I am (PSQL_1), the leader with the lock
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Štai antrinio mazgo žurnalo pavyzdys:
| patroni[753]: 2023-02-24 17:12:51,226 INFO: no action. I am (PSQL_2), a secondary, and following a leader (PSQL_1)
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Sugedus mazgui, iš etcd gauname tokią informaciją:
| etcd[691]: lost the TCP streaming connection with peer 2ec65eb059382a64 (stream MsgApp v2 reader)
etcd[691]: lost the TCP streaming connection with peer 2ec65eb059382a64 (stream Message reader)
etcd[691]: failed to dial 2ec65eb059382a64 on stream MsgApp v2 (dial tcp 10.68.250.1:2380: connect: connection refused)
etcd[691]: peer 2ec65eb059382a64 became inactive (message send to peer failed)
etcd[691]: lost the TCP streaming connection with peer 2ec65eb059382a64 (stream MsgApp v2 writer)
etcd[691]: lost the TCP streaming connection with peer 2ec65eb059382a64 (stream Message writer)
etcd[691]: health check for peer 2ec65eb059382a64 could not connect: dial tcp 10.68.250.1:2380: i/o timeout (prober "ROUND_TRIPPER_SNAPSHOT")
etcd[691]: health check for peer 2ec65eb059382a64 could not connect: dial tcp 10.68.250.1:2380: i/o timeout (prober "ROUND_TRIPPER_RAFT_MESSAGE")
etcd[691]: health check for peer 2ec65eb059382a64 could not connect: dial tcp 10.68.250.1:2380: i/o timeout (prober "ROUND_TRIPPER_SNAPSHOT")
etcd[691]: health check for peer 2ec65eb059382a64 could not connect: dial tcp 10.68.250.1:2380: i/o timeout (prober "ROUND_TRIPPER_RAFT_MESSAGE")
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Paskutiniai, paryškinti žurnalo įrašai kartojami cikliškai, kol sugedęs mazgas bus atkurtas.
Paslauga patroni taip pat įrašys į žurnalą kitos informacijos:
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19 | patroni[753]: 2023-02-24 17:14:41,221 INFO: no action. I am (PSQL_2), a secondary, and following a leader (PSQL_1)
patroni[753]: 2023-02-24 17:15:13,540 WARNING: Request failed to PSQL-CLUSTER1: GET https://10.68.250.1:8008/patroni (HTTPSConnectionPool(host='10.68.250.1', port=8008): Max retries exceeded with url: /patroni (Caused by ConnectTimeoutError(<urllib3.connection.VerifiedHTTPSConnection object at 0x7fa4e4762978>, 'Connection to 10.68.250.1 timed out. (connect timeout=2)')))
patroni[753]: 2023-02-24 17:15:13,646 INFO: Could not take out TTL lock
patroni[753]: 2023-02-24 17:15:13,654 INFO: following new leader after trying and failing to obtain lock
patroni[753]: 2023-02-24 17:15:13,794 INFO: closed patroni connection to the postgresql cluster
patroni[753]: 2023-02-24 17:15:13,987 INFO: postmaster pid=11704
patroni[753]: 2023-02-24 17:15:13.990 CET [11704] LOG: en écoute sur IPv4, adresse « 0.0.0.0 », port 5432
patroni[753]: 2023-02-24 17:15:13.990 CET [11704] LOG: en écoute sur IPv6, adresse « :: », port 5432
patroni[753]: /var/run/postgresql/:5432 - pas de réponse
patroni[753]: 2023-02-24 17:15:13.995 CET [11704] LOG: écoute sur la socket Unix « /var/run/postgresql/.s.PGSQL.5432 »
patroni[753]: 2023-02-24 17:15:14.006 CET [11704] LOG: redirection des traces vers le processus de récupération des traces
patroni[753]: 2023-02-24 17:15:14.006 CET [11704] ASTUCE : Les prochaines traces apparaîtront dans le répertoire « /var/log/postgresql ».
patroni[753]: /var/run/postgresql/:5432 - acceptation des connexions
patroni[753]: 2023-02-24 17:15:15,033 INFO: Lock owner: PSQL_3; I am PSQL_2
patroni[753]: 2023-02-24 17:15:15,033 INFO: establishing a new patroni connection to the postgres cluster
patroni[753]: 2023-02-24 17:15:15,036 INFO: Local timeline=1 lsn=0/402EE78
patroni[753]: 2023-02-24 17:15:15,066 INFO: master_timeline=2
patroni[753]: 2023-02-24 17:15:15,067 INFO: master: history=1 0/402EE78 no recovery target specified
patroni[753]: 2023-02-24 17:15:15,077 INFO: no action. I am (PSQL_2), a secondary, and following a leader (PSQL_3)
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Šiame pavyzdyje 1 eilutė nurodo, kad PSQL_2 yra LEADER mazgo PSQL_1 REPLICA. Antroji eilutė – klaidos pranešimas dėl prarasto ryšio su LEADER mazgu, o paskutinė eilutė nurodo, kad PSQL_2 vis dar yra REPLICA, tačiau šį kartą LEADER serverio PSQL_3.