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sysadm/data-silos/cassandra/installation.rst
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| .. _cassandra_installation: | ||||||||||
| How to install a cassandra node | ||||||||||
| =============================== | ||||||||||
| .. admonition:: Intended audience | ||||||||||
| :class: important | ||||||||||
| sysadm staff members | ||||||||||
| This page document the actions to configure a cassandra node and the associated instances | ||||||||||
| .. - Prepare the puppet configuration | ||||||||||
| Puppet configuration | ||||||||||
| -------------------- | ||||||||||
| Implicit configuration | ||||||||||
| ^^^^^^^^^^^^^^^^^^^^^^ | ||||||||||
| By default, each cassandra instance is isolated in its own repositories: | ||||||||||
| - `/etc/cassandra/<instance>`: the instance configuration | ||||||||||
| - `cassandra@<instance>`: the systemd service (configured with a template and a drop-in | ||||||||||
| directory `/etc/systemd/system/cassandra@<instance>.d`) | ||||||||||
| - `/var/log/cassandra/<instance>`: the log directory (the logs are also sent to the journal) | ||||||||||
| - `/srv/cassandra/<instance>/commitlog`: the commitlog directory. It should be configured on a | ||||||||||
| different zfs pool than the data directory | ||||||||||
| - `/srv/cassandra/<instance>/data`: the base data dir. The data, hints, system tables are stored | ||||||||||
| in this directory. | ||||||||||
| Declare the node | ||||||||||
| ^^^^^^^^^^^^^^^^ | ||||||||||
| In the `common/cassandra.yaml` file, declare the node configuration: | ||||||||||
| - Declare the node fqdn in the `cassandra::nodes` hash | ||||||||||
| - List all the instances that need to be installed on the node and their eventual overrides | ||||||||||
| - If the node is for a new cluster, also declare the cluster in the `cassandra::clusters` property | ||||||||||
| System installation | ||||||||||
| ------------------- | ||||||||||
| - Install the node with a debian bullseye distribution | ||||||||||
ardumontUnsubmitted Not Done Inline Actions
ardumont: | ||||||||||
| - Install zfs and configure the pools according to the instances that will run on the node. | ||||||||||
| Based on the usual cassandra server swh uses: | ||||||||||
| - one pool for the commitlogs using a fast write intensive disk | ||||||||||
| - one or several pools with the mixeduse disks | ||||||||||
Not Done Inline Actions
ardumont: | ||||||||||
| - If the server name starts with `cassandra[0-9]+`, puppet will install all the necessary | ||||||||||
| packages and the configured instances. | ||||||||||
| .. warning:: The services are just enabled, aka puppet doesn't force the service start. It's done | ||||||||||
| on purpose to let the system administrator control the restarts of the instances | ||||||||||
Not Done Inline Actions
ardumont: | ||||||||||
| - Check the configuration looks correct and start the instance(s) with `systemctl start cassandra@<instance>` | ||||||||||
| Monitoring | ||||||||||
| ^^^^^^^^^^ | ||||||||||
| TODO | ||||||||||
| Metric | ||||||||||
| ^^^^^^ | ||||||||||
| TODO | ||||||||||