### Problem to solve With https://gitlab.com/gitlab-org/gitlab-ce/issues/58941 we'll determine if Knative is already installed on cluster so users can take advantage of GitLab serverless features. However, the "install" button for Knative will still be present on the Kubernetes applications page. Two main problems arise: 1) Attempting installation will result in failure as Knative is already installed on cluster and 2) user will not be able to use domain/ingress configuration offered on this page. ### Intended users Operators, developers ### Further details <!-- Include use cases, benefits, and/or goals (contributes to our vision?) --> ### Proposal * Disable `Install` button if we detect Knative in their cluster. Change copy to `Installed`. This could be the case even if `Helm` is not yet installed which may need some additional frontend work depending on how the disabled applications were built. * Update documentation to include information regarding pre-existing Knative installations and how to fetch the external_ip / edit domain in those cases.  Following up issue for nice-to-have feature: https://gitlab.com/gitlab-org/gitlab-ce/issues/61347 ### Permissions and Security <!-- What permissions are required to perform the described actions? Are they consistent with the existing permissions as documented for users, groups, and projects as appropriate? Is the proposed behavior consistent between the UI, API, and other access methods (e.g. email replies)? --> ### Documentation <!-- See the Feature Change Documentation Workflow https://docs.gitlab.com/ee/development/documentation/feature-change-workflow.html Add all known Documentation Requirements here, per https://docs.gitlab.com/ee/development/documentation/feature-change-workflow.html#documentation-requirements --> ### Testing <!-- What risks does this change pose? How might it affect the quality of the product? What additional test coverage or changes to tests will be needed? Will it require cross-browser testing? See the test engineering process for further guidelines: https://about.gitlab.com/handbook/engineering/quality/guidelines/test-engineering/ --> ### What does success look like, and how can we measure that? <!-- Define both the success metrics and acceptance criteria. Note that success metrics indicate the desired business outcomes, while acceptance criteria indicate when the solution is working correctly. If there is no way to measure success, link to an issue that will implement a way to measure this. --> ### Links / references