Enable GitLabb runner to be uninstalled from cluster

- Set as uninstallable app
- Update docs
- Adjust specs

4 files changed, 14 insertions, 9 deletions

diff --git a/app/models/clusters/applications/runner.rb b/app/models/clusters/applications/runner.rb
index f0256ff4d41..599a100471c 100644
--- a/app/models/clusters/applications/runner.rb
+++ b/app/models/clusters/applications/runner.rb
@@ -17,6 +17,8 @@ module Clusters
 
       default_value_for :version, VERSION
 
+      after_destroy :destroy_ci_runner
+
       def chart
         "#{name}/gitlab-runner"
       end
@@ -29,13 +31,6 @@ module Clusters
         content_values.to_yaml
       end
 
-      # Need to investigate if pipelines run by this runner will stop upon the
-      # executor pod stopping
-      # I.e.run a pipeline, and uninstall runner while pipeline is running
-      def allowed_to_uninstall?
-        false
-      end
-
       def install_command
         Gitlab::Kubernetes::Helm::InstallCommand.new(
           name: name,
@@ -49,6 +44,10 @@ module Clusters
 
       private
 
+      def destroy_ci_runner
+        runner.destroy
+      end
+
       def ensure_runner
         runner || create_and_assign_runner
       end
diff --git a/changelogs/unreleased/60666-kubernetes-applications-uninstall-runner.yml b/changelogs/unreleased/60666-kubernetes-applications-uninstall-runner.yml
new file mode 100644
index 00000000000..3632c8eec20
--- /dev/null
+++ b/changelogs/unreleased/60666-kubernetes-applications-uninstall-runner.yml
@@ -0,0 +1,5 @@
+---
+title: Allow GitLab Runner to be uninstalled from the UI
+merge_request: 30176
+author:
+type: added
diff --git a/doc/user/clusters/applications.md b/doc/user/clusters/applications.md
index 469a7c09250..efad57c94ec 100644
--- a/doc/user/clusters/applications.md
+++ b/doc/user/clusters/applications.md
@@ -251,6 +251,7 @@ The applications below can be uninstalled.
 
 | Application | GitLab version | Notes |
 | ----------- | -------------- | ----- |
+| GitLab Runner  | 12.2+         | Any running pipelines will be canceled. |
 | Ingress  | 12.1+         | The associated load balancer and IP will be deleted and cannot be restored. Furthermore, it can only be uninstalled if JupyterHub is not installed. |
 | JupyterHub  | 12.1+         | All data not committed to GitLab will be deleted and cannot be restored. |
 | Prometheus  | 11.11+         | All data will be deleted and cannot be restored. |
@@ -278,7 +279,7 @@ Error: remote error: tls: bad certificate
 To avoid installation errors:
 
 - Before starting the installation of applications, make sure that time is synchronized
-  between your GitLab server and your Kubernetes cluster.
+between your GitLab server and your Kubernetes cluster.
 - Ensure certificates are not out of sync. When installing applications, GitLab expects a new cluster with no previous installation of Helm.
 
   You can confirm that the certificates match via `kubectl`:
diff --git a/spec/models/clusters/applications/runner_spec.rb b/spec/models/clusters/applications/runner_spec.rb
index 4f0cd0efe9c..b99f2e13675 100644
--- a/spec/models/clusters/applications/runner_spec.rb
+++ b/spec/models/clusters/applications/runner_spec.rb
@@ -18,7 +18,7 @@ describe Clusters::Applications::Runner do
 
     subject { gitlab_runner.can_uninstall? }
 
-    it { is_expected.to be_falsey }
+    it { is_expected.to be_truthy }
   end
 
   describe '#install_command' do