107 lines
6 KiB
Markdown
107 lines
6 KiB
Markdown
---
|
|
stage: none
|
|
group: unassigned
|
|
info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#designated-technical-writers
|
|
---
|
|
|
|
# Web terminals
|
|
|
|
> [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/merge_requests/7690) in GitLab 8.15.
|
|
|
|
NOTE: **Note:**
|
|
Only project maintainers and owners can access web terminals.
|
|
|
|
With the introduction of the [Kubernetes integration](../../user/project/clusters/index.md),
|
|
GitLab gained the ability to store and use credentials for a Kubernetes cluster.
|
|
One of the things it uses these credentials for is providing access to
|
|
[web terminals](../../ci/environments/index.md#web-terminals) for environments.
|
|
|
|
## How it works
|
|
|
|
A detailed overview of the architecture of web terminals and how they work
|
|
can be found in [this document](https://gitlab.com/gitlab-org/gitlab-workhorse/blob/master/doc/channel.md).
|
|
In brief:
|
|
|
|
- GitLab relies on the user to provide their own Kubernetes credentials, and to
|
|
appropriately label the pods they create when deploying.
|
|
- When a user navigates to the terminal page for an environment, they are served
|
|
a JavaScript application that opens a WebSocket connection back to GitLab.
|
|
- The WebSocket is handled in [Workhorse](https://gitlab.com/gitlab-org/gitlab-workhorse),
|
|
rather than the Rails application server.
|
|
- Workhorse queries Rails for connection details and user permissions. Rails
|
|
queries Kubernetes for them in the background using [Sidekiq](../troubleshooting/sidekiq.md).
|
|
- Workhorse acts as a proxy server between the user's browser and the Kubernetes
|
|
API, passing WebSocket frames between the two.
|
|
- Workhorse regularly polls Rails, terminating the WebSocket connection if the
|
|
user no longer has permission to access the terminal, or if the connection
|
|
details have changed.
|
|
|
|
## Security
|
|
|
|
GitLab and [GitLab Runner](https://docs.gitlab.com/runner/) take some
|
|
precautions to keep interactive web terminal data encrypted between them, and
|
|
everything protected with authorization guards. This is described in more
|
|
detail below.
|
|
|
|
- Interactive web terminals are completely disabled unless [`[session_server]`](https://docs.gitlab.com/runner/configuration/advanced-configuration.html#the-session_server-section) is configured.
|
|
- Every time the runner starts, it will generate an `x509` certificate that will be used for a `wss` (Web Socket Secure) connection.
|
|
- For every created job, a random URL is generated which is discarded at the end of the job. This URL is used to establish a web socket connection. The URL for the session is in the format `(IP|HOST):PORT/session/$SOME_HASH`, where the `IP/HOST` and `PORT` are the configured [`listen_address`](https://docs.gitlab.com/runner/configuration/advanced-configuration.html#the-session_server-section).
|
|
- Every session URL that is created has an authorization header that needs to be sent, to establish a `wss` connection.
|
|
- The session URL is not exposed to the users in any way. GitLab holds all the state internally and proxies accordingly.
|
|
|
|
## Enabling and disabling terminal support
|
|
|
|
NOTE: **Note:**
|
|
AWS Elastic Load Balancers (ELBs) do not support web sockets.
|
|
AWS Application Load Balancers (ALBs) must be used if you want web terminals
|
|
to work. See [AWS Elastic Load Balancing Product Comparison](https://aws.amazon.com/elasticloadbalancing/features/#compare)
|
|
for more information.
|
|
|
|
As web terminals use WebSockets, every HTTP/HTTPS reverse proxy in front of
|
|
Workhorse needs to be configured to pass the `Connection` and `Upgrade` headers
|
|
through to the next one in the chain. If you installed GitLab using Omnibus, or
|
|
from source, starting with GitLab 8.15, this should be done by the default
|
|
configuration, so there's no need for you to do anything.
|
|
|
|
However, if you run a [load balancer](../load_balancer.md) in
|
|
front of GitLab, you may need to make some changes to your configuration. These
|
|
guides document the necessary steps for a selection of popular reverse proxies:
|
|
|
|
- [Apache](https://httpd.apache.org/docs/2.4/mod/mod_proxy_wstunnel.html)
|
|
- [NGINX](https://www.nginx.com/blog/websocket-nginx/)
|
|
- [HAProxy](https://www.haproxy.com/blog/websockets-load-balancing-with-haproxy/)
|
|
- [Varnish](https://varnish-cache.org/docs/4.1/users-guide/vcl-example-websockets.html)
|
|
|
|
Workhorse won't let WebSocket requests through to non-WebSocket endpoints, so
|
|
it's safe to enable support for these headers globally. If you'd rather had a
|
|
narrower set of rules, you can restrict it to URLs ending with `/terminal.ws`
|
|
(although this may still have a few false positives).
|
|
|
|
If you installed from source, or have made any configuration changes to your
|
|
Omnibus installation before upgrading to 8.15, you may need to make some changes
|
|
to your configuration. See the [Upgrading Community Edition and Enterprise
|
|
Edition from source](../../update/upgrading_from_source.md#nginx-configuration)
|
|
document for more details.
|
|
|
|
If you'd like to disable web terminal support in GitLab, just stop passing
|
|
the `Connection` and `Upgrade` hop-by-hop headers in the *first* HTTP reverse
|
|
proxy in the chain. For most users, this will be the NGINX server bundled with
|
|
Omnibus GitLab, in which case, you need to:
|
|
|
|
- Find the `nginx['proxy_set_headers']` section of your `gitlab.rb` file
|
|
- Ensure the whole block is uncommented, and then comment out or remove the
|
|
`Connection` and `Upgrade` lines.
|
|
|
|
For your own load balancer, just reverse the configuration changes recommended
|
|
by the above guides.
|
|
|
|
When these headers are not passed through, Workhorse will return a
|
|
`400 Bad Request` response to users attempting to use a web terminal. In turn,
|
|
they will receive a `Connection failed` message.
|
|
|
|
## Limiting WebSocket connection time
|
|
|
|
> [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/-/merge_requests/8413) in GitLab 8.17.
|
|
|
|
Terminal sessions, by default, do not expire.
|
|
You can limit terminal session lifetime in your GitLab instance. To do so, navigate to [**Admin Area > Settings > Web terminal**](../../user/admin_area/settings/index.md#general), and set a `max session time`.
|