# Debugging a failing image without a deployment **URL:** \ **Category:** General\ **Created:** [May 25, 2021, 6:08pm UTC](https://community.fly.io/t/debugging-a-failing-image-without-a-deployment/1545 "2021-05-25T18:08:37Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![jsierles](https://sea1.discourse-cdn.com/fly1/user_avatar/community.fly.io/jsierles/32/595_2.png) [@jsierles](https://community.fly.io/u/jsierles)\ **Post date:** [May 25, 2021, 6:08pm UTC](https://community.fly.io/t/debugging-a-failing-image-without-a-deployment/1545/1 "2021-05-25T18:08:37Z")
Occasionally I want to try a pre-built image from Dockerhub on Fly. To get it setup with all its requirements (like a database URL, etc), it would be useful to be able to run an image on a small VM with a shell command, _without_ having to have a successful web deployment. Is this possible right now somehow? ---
**Author:** ![kurt](https://sea1.discourse-cdn.com/fly1/user_avatar/community.fly.io/kurt/32/43757_2.png) [@kurt](https://community.fly.io/u/kurt)\ **Post date:** [May 25, 2021, 6:18pm UTC](https://community.fly.io/t/debugging-a-failing-image-without-a-deployment/1545/2 "2021-05-25T18:18:48Z")
It’s possible, but more complex than I’d like. What I do is create a `Dockerfile` with `FROM `, add bash if it’s not already there, override `CMD` to start a stub long running process (you might have to override `ENTRYPOINT` as well). Then deploy and use `fly ssh console` to get a shell and start poking. I wonder if we can make this easier without many changes. Seems like “boot a Firecracker and keep it alive” might be doable. ---
**Author:** ![jsierles](https://sea1.discourse-cdn.com/fly1/user_avatar/community.fly.io/jsierles/32/595_2.png) [@jsierles](https://community.fly.io/u/jsierles)\ **Post date:** [May 25, 2021, 6:23pm UTC](https://community.fly.io/t/debugging-a-failing-image-without-a-deployment/1545/3 "2021-05-25T18:23:52Z")
Cool, thanks. One other thing that came up with this scenario is the Docker image expecting a `REDIS_URL`. I’d like to use the existing Redis cache instance. If I extract `FLY_REDIS_CACHE_URL` from a running instance, can I then set `REDIS_URL` without fear? Having a built-in way to do this would be cool too. ---
**Author:** ![kurt](https://sea1.discourse-cdn.com/fly1/user_avatar/community.fly.io/kurt/32/43757_2.png) [@kurt](https://community.fly.io/u/kurt)\ **Post date:** [May 25, 2021, 6:25pm UTC](https://community.fly.io/t/debugging-a-failing-image-without-a-deployment/1545/4 "2021-05-25T18:25:32Z")
You should be able to use that URL for `REDIS_CACHE_URL`. We _probably_ won’t make that magical, our shared Redis cache has been deprecated and people are better off running redis processes themselves for the most part. We might introduce a `fly redis` command that behaves like Postgres, though, it’s relatively straightforward. ---
**Author:** ![jsierles](https://sea1.discourse-cdn.com/fly1/user_avatar/community.fly.io/jsierles/32/595_2.png) [@jsierles](https://community.fly.io/u/jsierles)\ **Post date:** [May 25, 2021, 6:33pm UTC](https://community.fly.io/t/debugging-a-failing-image-without-a-deployment/1545/5 "2021-05-25T18:33:24Z")
OK, good to know it’s been deprecated! ---
**Author:** ![tullo](https://sea1.discourse-cdn.com/fly1/user_avatar/community.fly.io/tullo/32/1633_2.png) [@tullo](https://community.fly.io/u/tullo)\ **Post date:** [November 19, 2021, 9:32pm UTC](https://community.fly.io/t/debugging-a-failing-image-without-a-deployment/1545/6 "2021-11-19T21:32:42Z")
Where is it announced that shared redis is depreciated? The reference does not mention it. > **[Upstash for Redis®\*](https://fly.io/docs/reference/redis/)** > > Documentation and guides from the team at Fly.io. ---
**Author:** ![sudhir.j](https://sea1.discourse-cdn.com/fly1/user_avatar/community.fly.io/sudhir.j/32/39775_2.png) [@sudhir.j](https://community.fly.io/u/sudhir.j)\ **Post date:** [November 23, 2021, 9:32am UTC](https://community.fly.io/t/debugging-a-failing-image-without-a-deployment/1545/7 "2021-11-23T09:32:37Z")
@tullo It’s deprecated in the sense that we don’t recommend people use it much — there are better ways to run Redis, especially if you’re using it for something serious. But it does still work as documented.