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 the PostgreSQL database
+layout: post
+author: Ilya Buziuk
+description: >-
+  The article describes how the PostgreSQL database dependency has been removed in Eclipse Che
+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)
+----
+
+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 and Devfile v2], all this data become irrelevant since we start using native Kubernetes resources instead.
+
+The data is now stored and managed as Kubernetes resources such as Secrets and ConfigMaps in the user namespaces:
+
+image::/assets/img/decommissioning-postgresql-database/secrets.png[Secrets from the user namespace]
+
+image::/assets/img/decommissioning-postgresql-database/configmaps.png[ConfigMaps from the user namespace]
+{nbsp} +
+
+As an example, 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` release PostgreSQL deployment cease to exist and we now have only 5 operands: Che Server, User Dashboard, Plugin Registry, Devfile Registry, and Gateway.
+
+image::/assets/img/decommissioning-postgresql-database/operands.png[{prod} operands]
+{nbsp} +
+
+IMPORTANT: No manual migration steps and action items are required. PostgreSQL deployment will be gracefully terminated and removed during the update. All the obsolete data stored in the database will be removed.
+
+It is also worth mentioning that most of the `https://<che_fqdn>/swagger` endpoints are now deprecated and going to be removed in future releases. The only endpoints that are still used are related to the namespace provisioning, Git OAuth configuration, and the factory flow: 
+
+- /kubernetes/namespace/*
+- /oauth/*
+- /factory/*
+
+== Next steps
+
+Decommissioning the PostgreSQL database in favor of native Kubernetes resources provides several benefits, including improved scalability, flexibility, and easier management. 
+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, which was not possible before due to the PostgreSQL database dependency:
+
+[source,bash]
+spec:
+  components:
+    cheServer:
+      deployment:
+        replicas: 1
+    dashboard:
+      deployment:
+        replicas: 1
+    devfileRegistry:
+      deployment:
+        replicas: 1
+    pluginRegistry:
+      deployment:
+        replicas: 1
+[source,bash]
+
+The progress 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].
+{nbsp} +
+We wish you an enjoyable and productive coding experience with {prod}!