### Motivation
PR #3167 introduced the tap APIService and migrated `linkerd tap` to use it.
Subsequent PRs (#3186 and #3187) updated `linkerd top` and `linkerd profile
--tap` to use the tap APIService. This PR moves the web's Go server to now also
use the tap APIService instead of the public API. It also ensures an error
banner is shown to the user when unauthorized taps fail via `linkerd top`
command in *Overview* and *Top*, and `linkerd tap` command in *Tap*.
### Details
The majority of these changes are focused around piping through the HTTP error
that occurs and making sure the error banner generated displays the error
message explaining to view the tap RBAC docs.
`httpError` is now public (`HTTPError`) and the error message generated is short
enough to fit in a control frame (explained [here](https://github.com/linkerd/linkerd2/blob/kleimkuhler%2Fweb-tap-apiserver/web/srv/api_handlers.go#L173-L175)).
### Testing
The error we are testing for only occurs when the linkerd-web service account is
not authorzied to tap resources. Unforutnately that is not the case on Docker
For Mac (assuming that is what you use locally), so you'll need to test on a
different cluster. I chose a GKE cluster made through the GKE console--not made
through cluster-utils because it adds cluster-admin.
Checkout the branch locally and `bin/docker-build` or `ares-build` if you have
it setup. It should produce a linkerd with the version `git-04e61786`. I have
already pushed the dependent components, so you won't need to `bin/docker-push
git-04e61786`.
Install linkerd on this GKE cluster and try to run `tap` or `top` commands via
the web. You should see the following errors:
### Tap
### Top
Signed-off-by: Kevin Leimkuhler <kleimkuhler@icloud.com>
The Tap Service enabled tapping of any meshed pod, regardless of user
privilege.
This change introduces a new Tap APIService. Kubernetes provides
authentication and authorization of Tap requests, and then forwards
requests to a new Tap APIServer, which implements a Kubernetes
aggregated APIServer. The Tap APIServer authenticates the client TLS
from Kubernetes, and authorizes the user via a SubjectAccessReview.
This change also modifies the `linkerd tap` command to make requests
against the new APIService.
The Tap APIService implements these Kubernetes-style endpoints:
POST /apis/tap.linkerd.io/v1alpha1/watch/namespaces/:ns/tap
POST /apis/tap.linkerd.io/v1alpha1/watch/namespaces/:ns/:res/:name/tap
GET /apis
GET /apis/tap.linkerd.io
GET /apis/tap.linkerd.io/v1alpha1
GET /healthz
GET /healthz/log
GET /healthz/ping
GET /metrics
GET /openapi/v2
GET /version
Users authorize to the new `tap.linkerd.io/v1alpha1` via RBAC. Only the
`watch` verb is supported. Access is also available via subresources
such as `deployments/tap` and `pods/tap`.
This change introduces the following resources into the default Linkerd
install:
- Global
- APIService/v1alpha1.tap.linkerd.io
- ClusterRoleBinding/linkerd-linkerd-tap-auth-delegator
- `linkerd` namespace:
- Secret/linkerd-tap-tls
- `kube-system` namespace:
- RoleBinding/linkerd-linkerd-tap-auth-reader
Tasks not covered by this PR:
- `linkerd top`
- `linkerd dashboard`
- `linkerd profile --tap`
- removal of the unauthenticated tap controller
Fixes#2725, #3162, #3172
Signed-off-by: Andrew Seigner <siggy@buoyant.io>
Andrew Seigner
Kevin Leimkuhler
