{"id":7675,"date":"2016-04-19T15:19:46","date_gmt":"2016-04-19T13:19:46","guid":{"rendered":"https:\/\/www.dbi-services.com\/blog\/maintenance-scenarios-with-edb-failover-manager-3-witness-node\/"},"modified":"2016-04-19T15:19:46","modified_gmt":"2016-04-19T13:19:46","slug":"maintenance-scenarios-with-edb-failover-manager-3-witness-node","status":"publish","type":"post","link":"https:\/\/www.dbi-services.com\/blog\/maintenance-scenarios-with-edb-failover-manager-3-witness-node\/","title":{"rendered":"Maintenance scenarios with EDB Failover Manager (3) \u2013 Witness node"},"content":{"rendered":"

In the last posts ( Maintenance scenarios with EDB Failover Manager (1) \u2013 Standby node <\/a>, Maintenance scenarios with EDB Failover Manager (2) \u2013 Primary node<\/a> ) we looked at how to perform maintenance operations on the master as well as on the standby node in a failover cluster managed by EDB Failober Manager<\/a>. What is still open is how to perform maintenance operations on the witness node. So, lets go.<\/p>\n

<\/p>\n

The current status of the cluster is fine:<\/p>\n

\npostgres@edbbart:\/home\/postgres\/ [pg950] \/usr\/efm-2.0\/bin\/efm cluster-status efm\nCluster Status: efm\nAutomatic failover is disabled.\n\n\tAgent Type  Address              Agent  DB       Info\n\t--------------------------------------------------------------\n\tStandby     192.168.22.243       UP     UP        \n\tWitness     192.168.22.244       UP     N\/A       \n\tMaster      192.168.22.245       UP     UP        \n\nAllowed node host list:\n\t192.168.22.244 192.168.22.243 192.168.22.245\n\nStandby priority host list:\n\t192.168.22.243\n\nPromote Status:\n\n\tDB Type     Address              XLog Loc         Info\n\t--------------------------------------------------------------\n\tMaster      192.168.22.245       0\/380000D0       \n\tStandby     192.168.22.243       0\/380000D0       \n\n\tStandby database(s) in sync with master. It is safe to promote.\n<\/pre>\n
Probably the only situations you’ll need to take care of is when you want to reboot the witness node for any reason or when you need to take down the efm service. What happens when you stop the service on the witness?<\/p>\n
\n[root@edbbart ~] systemctl stop efm-2.0.service\n<\/pre>\n
Checking the status on either the master or the standby node:<\/p>\n
\n[root@ppasstandby efm-2.0] \/usr\/efm-2.0\/bin\/efm cluster-status efm\nCluster Status: efm\nAutomatic failover is disabled.\n\n\tAgent Type  Address              Agent  DB       Info\n\t--------------------------------------------------------------\n\tStandby     192.168.22.243       UP     UP        \n\tMaster      192.168.22.245       UP     UP        \n\nAllowed node host list:\n\t192.168.22.244 192.168.22.243 192.168.22.245\n\nStandby priority host list:\n\t192.168.22.243\n\nPromote Status:\n\n\tDB Type     Address              XLog Loc         Info\n\t--------------------------------------------------------------\n\tMaster      192.168.22.245       0\/380000D0       \n\tStandby     192.168.22.243       0\/380000D0       \n\n\tStandby database(s) in sync with master. It is safe to promote.\n<\/pre>\n
The witness disappeared. How to bring it back? Re-create the efm.nodes file on the witness node:<\/p>\n
\n[root@edbbart efm-2.0] pwd\n\/etc\/efm-2.0\n[root@edbbart efm-2.0] cat efm.nodes\n# List of node address:port combinations separated by whitespace.\n192.168.22.243:9998 192.168.22.244:9998 192.168.22.245:9998\n<\/pre>\n
Start the service:<\/p>\n
\n[root@edbbart efm-2.0] systemctl start efm-2.0.service\n<\/pre>\n
… and you’ll be back in business:<\/p>\n
\n[root@edbbart efm-2.0] \/usr\/edb-efm\/bin\/efm cluster-status efm \nCluster Status: efm\nAutomatic failover is disabled.\n\n\tAgent Type  Address              Agent  DB       Info\n\t--------------------------------------------------------------\n\tMaster      192.168.22.245       UP     UP        \n\tWitness     192.168.22.244       UP     N\/A       \n\tStandby     192.168.22.243       UP     UP        \n\nAllowed node host list:\n\t192.168.22.244 192.168.22.243 192.168.22.245\n\nStandby priority host list:\n\t192.168.22.243\n\nPromote Status:\n\n\tDB Type     Address              XLog Loc         Info\n\t--------------------------------------------------------------\n\tMaster      192.168.22.245       0\/380000D0       \n\tStandby     192.168.22.243       0\/380000D0       \n\n\tStandby database(s) in sync with master. It is safe to promote.\n<\/pre>\n
What do you need to do in case you need to reboot? Exactly the same \ud83d\ude42 Quite easy when you want to do maintenance on the witness node. <\/p>\n
Btw: If you want you can meet us at the Swiss PGDAY<\/a>, Agenda here<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
In the last posts ( Maintenance scenarios with EDB Failover Manager (1) \u2013 Standby node , Maintenance scenarios with EDB Failover Manager (2) \u2013 Primary node ) we looked at how to perform maintenance operations on the master as well as on the standby node in a failover cluster managed by EDB Failober Manager. What […]<\/p>\n","protected":false},"author":29,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[229],"tags":[713,464,77,238],"type_dbi":[],"class_list":["post-7675","post","type-post","status-publish","format-standard","hentry","category-database-administration-monitoring","tag-enterprisedb","tag-failover-cluster","tag-postgresql","tag-standby"],"acf":[],"yoast_head":"\nMaintenance scenarios with EDB Failover Manager (3) \u2013 Witness node - dbi Blog<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.dbi-services.com\/blog\/maintenance-scenarios-with-edb-failover-manager-3-witness-node\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Maintenance scenarios with EDB Failover Manager (3) \u2013 Witness node\" \/>\n<meta property=\"og:description\" content=\"In the last posts ( Maintenance scenarios with EDB Failover Manager (1) \u2013 Standby node , Maintenance scenarios with EDB Failover Manager (2) \u2013 Primary node ) we looked at how to perform maintenance operations on the master as well as on the standby node in a failover cluster managed by EDB Failober Manager. 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He has more than 15 years of experience in management, engineering and optimization of databases and infrastructures, especially on Oracle and PostgreSQL. Since the beginning of his career, he has specialized in Oracle Technologies and is Oracle Certified Professional 12c and Oracle Certified Expert RAC\/GridInfra. Over time, Daniel has become increasingly interested in open source technologies, becoming \u201cTechnology Leader Open Infrastructure\u201d and PostgreSQL expert. \u00a0Based on community or EnterpriseDB tools, he develops and installs complex high available solutions with PostgreSQL. He is also a certified PostgreSQL Plus 9.0 Professional and a Postgres Advanced Server 9.4 Professional. He is a regular speaker at PostgreSQL conferences in Switzerland and Europe. Today Daniel is also supporting our customers on AWS services such as AWS RDS, database migrations into the cloud, EC2 and automated infrastructure management with AWS SSM (System Manager). 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He has more than 15 years of experience in management, engineering and optimization of databases and infrastructures, especially on Oracle and PostgreSQL. Since the beginning of his career, he has specialized in Oracle Technologies and is Oracle Certified Professional 12c and Oracle Certified Expert RAC\/GridInfra. Over time, Daniel has become increasingly interested in open source technologies, becoming \u201cTechnology Leader Open Infrastructure\u201d and PostgreSQL expert. \u00a0Based on community or EnterpriseDB tools, he develops and installs complex high available solutions with PostgreSQL. He is also a certified PostgreSQL Plus 9.0 Professional and a Postgres Advanced Server 9.4 Professional. He is a regular speaker at PostgreSQL conferences in Switzerland and Europe. Today Daniel is also supporting our customers on AWS services such as AWS RDS, database migrations into the cloud, EC2 and automated infrastructure management with AWS SSM (System Manager). He is a certified AWS Solutions Architect Professional. Prior to dbi services, Daniel was Management System Engineer at LC SYSTEMS-Engineering AG in Basel. Before that, he worked as Oracle Developper &\u00a0Project Manager at Delta Energy Solutions AG in Basel (today Powel AG). Daniel holds a diploma in Business Informatics (DHBW, Germany). His branch-related experience mainly covers the pharma industry, the financial sector, energy, lottery and telecommunications.","sameAs":["https:\/\/x.com\/westermanndanie"],"url":"https:\/\/www.dbi-services.com\/blog\/author\/daniel-westermann\/"}]}},"_links":{"self":[{"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/posts\/7675","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/users\/29"}],"replies":[{"embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/comments?post=7675"}],"version-history":[{"count":0,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/posts\/7675\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/media?parent=7675"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/categories?post=7675"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/tags?post=7675"},{"taxonomy":"type","embeddable":true,"href":"https:\/\/www.dbi-services.com\/blog\/wp-json\/wp\/v2\/type_dbi?post=7675"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}