This is the process for in-place upgrades of Elasticsearch (ES), using an existing Search feed and index data.
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Upgrading Elasticsearch by script
On each node in an Elasticsearch cluster, follow this process and run the files from the Swarm download bundle:
Query the running Elasticsearch cluster, before upgrading, for the list of nodes.
Code Block language bash curl -i http://ELASTICSEARCH:9200/_cat/nodesNote which node is starred. That is the Elasticsearch master node which is recommended to upgrade last to avoid problems electing a new one.
Backup the existing elasticsearch.yml, so a record of any customizations made exists.
Create a symbolic (soft) link:
symlink /var/lib/elasticsearchif path.data is customized . Perform the upgrade manually, as described below if unable.Start by installing the latest Swarm Search, which is the
caringo-elasticsearch-searchRPM when upgrading Elasticsearch 6.Code Block language bash yum install caringo-elasticsearch-search-VERSION.noarch.rpmInfo title Tip The error: "
ES_PATH_CONF must be set to the configuration path chown: cannot access '/etc/elasticsearch/elasticsearch.keystore': No such file or directory" displays if Elasticsearch 7 RPM is inadvertently installed. Install caringo-elasticsearch-search-7.0.0 RPM to proceed.Run the script that installs and configures the upgrade.
The script detects Elasticsearch 6 is installed anddiscovery.zen.unicast.hostsis configured, so it runs as with--upgradeinstead of configuring a new cluster.Code Block language bash /usr/share/caringo-elasticsearch-search/bin/configure_elasticsearch_with_swarm_search.pyCompare the backup file to the newly created
elasticsearch.ymland add back any customizations needed, such asnetwork.host(which defaults to_site_,
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all interfaces).
Verify all nodes are accounted for, all shards are assigned, and the status is green.
Code Block language bash curl -i 'http://ELASTICSEARCH:9200/_cat/health?v'
The script updates the configuration files and restarts the service if Elasticsearch 7 is already installed.
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TroubleshootingChange permissions |
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if the Elasticsearch service fails |
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ImportantType Ctrl-C once, whenever the upgrade script is stuck in retrying status checks and proceed to the next node after the script finishes if the cluster loses master during the upgrade process and does not recover. Review The nodes elect the master and recover once all nodes have started on Elasticsearch 7.5.2. Health status goes yellow then eventually green. Re-enable shard allocation, otherwise |
Upgrading Elasticsearch manually
These are the steps the script automates if needing to upgrade manually:
It fixes
/etc/sysconfig/elasticsearchto be the correct ES6 version (it's also the same as ES7).It increases the
systemdtimeout in/etc/systemd/system/elasticsearch.service.d/override.conf(see github.com/elastic/elasticsearch/issues/60140)A prompt to continue with the yum upgrade to 7.5.2 appears after refreshing the config files for Elasticsearch 6.
It disables shard allocation and does a POST synced-flush for safer rolling upgrades.
Info title Important Disabling shard allocation or sync-flush can fail to contact the node, but do not proceed to upgrade the next node until the cluster health is green again.
It uninstalls the Prometheus Exporter plugin if it exists.
It shells out to yum to install the Elasticsearch 7 RPM in the current directory or from artifacts.elastic.co, if unavailable.
Warning Internet access is expected for the upgrade. Verify the Elasticsearch RPM is in the current directory if access is unavailable.
It updates elasticsearch.yml for version 7 compatibility, including
discovery.initial_master_nodesinstead ofdiscovery.zen.unicast.hosts, andjvm.options.It starts the upgraded Elasticsearch 7 and waits for it to be ready.
The cluster re-enables shard allocation and prompts to repeat these two steps on the next node if the cluster health is green or yellow.