feat: Decommissioning PostgreSQL database

Signed-off-by: Ilya Buziuk <[email protected]>

_posts/2023-03-20-decommissioning-postgresql-database.adoc

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+---
+title: Decommissioning PostgreSQL database
+layout: post
+author: Ilya Buziuk
+description: >-
+  The article describes how the PostgreSQL database dependency has been removed in {prod}
+categories: []
+keywords: ['postgresql']
+slug: /@ilya.buziuk/decommissioning-postgresql-database
+---
+
+Historically {prod} used PostgreSQL database for storing relevant information about the users, workspaces, devfiles, preferences, SSH keys, etc.
+Overall there were dozens of tables in the database which represent the state of the {prod} instance:
+
+[source,bash]
+----
+psql (13.7)
+Type "help" for help.
+
+dbche=> \dt
+                            List of relations
+ Schema |                      Name                       | Type  | Owner 
+--------+-------------------------------------------------+-------+-------
+ public | account                                         | table | pgche
+ public | che_factory                                     | table | pgche
+ public | che_factory_action                              | table | pgche
+ public | che_factory_action_properties                   | table | pgche
+ public | che_factory_ide                                 | table | pgche
+ public | che_factory_on_app_closed_action                | table | pgche
+ public | che_factory_on_app_closed_action_value          | table | pgche
+ public | che_factory_on_app_loaded_action                | table | pgche
+ public | che_factory_on_app_loaded_action_value          | table | pgche
+ public | che_factory_on_projects_loaded_action           | table | pgche
+ public | che_factory_on_projects_loaded_action_value     | table | pgche
+ public | che_free_resources_limit                        | table | pgche
+ public | che_free_resources_limit_resource               | table | pgche
+ public | che_k8s_machine                                 | table | pgche
+ public | che_k8s_machine_attributes                      | table | pgche
+ public | che_k8s_runtime                                 | table | pgche
+ public | che_k8s_server                                  | table | pgche
+ public | che_k8s_server_attributes                       | table | pgche
+ public | che_member                                      | table | pgche
+ public | che_member_actions                              | table | pgche
+ public | che_organization                                | table | pgche
+ public | che_organization_distributed_resources          | table | pgche
+ public | che_organization_distributed_resources_resource | table | pgche
+ public | che_resource                                    | table | pgche
+ public | che_sign_key                                    | table | pgche
+ public | che_sign_key_pair                               | table | pgche
+ public | che_system_permissions                          | table | pgche
+ public | che_system_permissions_actions                  | table | pgche
+ public | che_userdevfile_permissions                     | table | pgche
+ public | che_userdevfile_permissions_actions             | table | pgche
+ public | che_worker                                      | table | pgche
+ public | che_worker_actions                              | table | pgche
+ public | che_workspace_activity                          | table | pgche
+ public | che_workspace_cfg_attributes                    | table | pgche
+ public | command                                         | table | pgche
+ public | command_attributes                              | table | pgche
+ public | devfile                                         | table | pgche
+ public | devfile_action                                  | table | pgche
+ public | devfile_attributes                              | table | pgche
+ public | devfile_command                                 | table | pgche
+ public | devfile_command_attributes                      | table | pgche
+ public | devfile_component                               | table | pgche
+ public | devfile_component_arg                           | table | pgche
+ public | devfile_component_command                       | table | pgche
+ public | devfile_component_preferences                   | table | pgche
+ public | devfile_component_selector                      | table | pgche
+ public | devfile_endpoint                                | table | pgche
+ public | devfile_endpoint_attributes                     | table | pgche
+ public | devfile_entrypoint                              | table | pgche
+ public | devfile_entrypoint_arg                          | table | pgche
+ public | devfile_entrypoint_commands                     | table | pgche
+ public | devfile_entrypoint_selector                     | table | pgche
+ public | devfile_env                                     | table | pgche
+ public | devfile_project                                 | table | pgche
+ public | devfile_volume                                  | table | pgche
+ public | environment                                     | table | pgche
+ public | externalmachine                                 | table | pgche
+ public | externalmachine_attributes                      | table | pgche
+ public | externalmachine_env                             | table | pgche
+ public | k8s_runtime_command                             | table | pgche
+ public | k8s_runtime_command_attributes                  | table | pgche
+ public | machine_volume                                  | table | pgche
+ public | preference                                      | table | pgche
+ public | preference_preferences                          | table | pgche
+ public | profile                                         | table | pgche
+ public | profile_attributes                              | table | pgche
+ public | projectattribute                                | table | pgche
+ public | projectattribute_values                         | table | pgche
+ public | projectconfig                                   | table | pgche
+ public | projectconfig_mixins                            | table | pgche
+ public | schema_version                                  | table | pgche
+ public | sequence                                        | table | pgche
+ public | serverconf                                      | table | pgche
+ public | serverconf_attributes                           | table | pgche
+ public | serverconf_properties                           | table | pgche
+ public | sourcestorage                                   | table | pgche
+ public | sourcestorage_parameters                        | table | pgche
+ public | sshkeypair                                      | table | pgche
+ public | user_aliases                                    | table | pgche
+ public | userdevfile                                     | table | pgche
+ public | usr                                             | table | pgche
+ public | workspace                                       | table | pgche
+ public | workspace_attributes                            | table | pgche
+ public | workspaceconfig                                 | table | pgche
+(84 rows)
+----
+{nbsp} +
+
+However, with the switch to link:https://che.eclipseprojects.io/2021/10/12/@mario.loriedo-devfile-v2-and-the-devworkspace-operator-p1.html[DevWorkspace Operator], all this data become irrelevant since we start using native Kubernetes resources instead.
+For instance, SSH keys are now configured using the dedicated link:https://github.com/devfile/devworkspace-operator/blob/main/docs/additional-configuration.adoc#configuring-devworkspaces-to-use-ssh-keys-for-git-operations[secret].
+
+Starting from {prod} `7.62.0` version PostgreSQL operand cease to exist and we now only have 5 operands: Che Server, Dashboard, Plugin Registry, Devfile Registry, and Gateway. 
+
+image::/assets/img/decommissioning-postgresql-database/operands.png[{prod} operands]
+
+From now on, all the relevant data is stored as Kubernetes resources such as Secrets and ConfigMaps in the user namespaces which makes database enty irrelevant.
+
+image::/assets/img/decommissioning-postgresql-database/secrets.png[Secrets from the user namespace]
+
+{nbsp} +
+
+image::/assets/img/decommissioning-postgresql-database/configmaps.png[ConfigMaps from the user namespace]
+
+It also worth mentioning that most of the https://<che_fqdn>/swagger endpoints are now deprecated. The only endpoints that are not going to be deprecated are related to namespace provisioning, factory, and Git OAuth flow: 
+
+- /kubernetes/namespace/*
+- /factory/*
+- /oauth/*
+
+== Next steps
+
+Decommissioning a PostgreSQL database in favor of native Kubernetes provides several benefits, including improved scalability, flexibility, and easier management of resources. 
+Ultimately, moving away from traditional database architectures and embracing Kubernetes makes {prod} agile and competitive in an increasingly complex and demanding technology landscape.
+In the next {prod} releases we plan to make it possible to configure a number of replicas for operands from the CheCluster CustomResource:
+
+[source,bash]
+spec:
+  components:
+    cheServer:
+      deployment:
+        replicas: 1
+    dashboard:
+      deployment:
+        replicas: 1
+    devfileRegistry:
+      deployment:
+        replicas: 1
+    pluginRegistry:
+      deployment:
+        replicas: 1
+[source,bash]
+
+The progess can be tracked in the upstream link:https://github.com/eclipse/che/issues/22067[issue]. 
+We anticipate receiving your valuable feedback, comments, remarks, and proposals on our link:https://accounts.eclipse.org/mailing-list/che-dev[mailing list], link:https://github.com/eclipse/che/issues[GitHub], and link:https://mattermost.eclipse.org/eclipse/channels/eclipse-che[Mattermost].
+We wish you an enjoyable and productive coding experience with {prod}!