while type

prefect server start

it say

ERROR: Couldn't connect to Docker daemon at <http+docker://localhost> - is it running?

but the docker is up and running could someone help me please ? the full error

amir@server:~$ prefect server start
ERROR: Couldn't connect to Docker daemon at <http+docker://localhost> - is it running?

If it's at a non-standard location, specify the URL with the DOCKER_HOST environment variable.
Exception caught; killing services (press ctrl-C to force)
ERROR: Couldn't connect to Docker daemon at <http+docker://localhost> - is it running?

If it's at a non-standard location, specify the URL with the DOCKER_HOST environment variable.
Traceback (most recent call last):
  File "/home/amir/.local/lib/python3.8/site-packages/prefect/cli/server.py", line 623, in start
    subprocess.check_call(
  File "/usr/lib/python3.8/subprocess.py", line 364, in check_call
    raise CalledProcessError(retcode, cmd)
subprocess.CalledProcessError: Command '['docker-compose', 'pull']' returned non-zero exit status 1.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/amir/.local/bin/prefect", line 8, in <module>
    sys.exit(cli())
  File "/usr/lib/python3/dist-packages/click/core.py", line 764, in __call__
    return self.main(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/click/core.py", line 717, in main
    rv = self.invoke(ctx)
  File "/usr/lib/python3/dist-packages/click/core.py", line 1137, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/lib/python3/dist-packages/click/core.py", line 1137, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/usr/lib/python3/dist-packages/click/core.py", line 956, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/lib/python3/dist-packages/click/core.py", line 555, in invoke
    return callback(*args, **kwargs)
  File "/home/amir/.local/lib/python3.8/site-packages/prefect/cli/server.py", line 664, in start
    subprocess.check_output(
  File "/usr/lib/python3.8/subprocess.py", line 415, in check_output
    return run(*popenargs, stdout=PIPE, timeout=timeout, check=True,
  File "/usr/lib/python3.8/subprocess.py", line 516, in run
    raise CalledProcessError(retcode, process.args,
subprocess.CalledProcessError: Command '['docker-compose', 'down']' returned non-zero exit status 1.

@alins could you move the code block into the thread to keep the main channel a bit cleaner? Tom has recently faced the same issue, could you try the solution from this thread https://prefect-community.slack.com/archives/C014Z8DPDSR/p1637331372490700?thread_ts=1637331372.490700&cid=C014Z8DPDSR ? In short, your Docker daemon is not configured properly. You need to install both Docker and docker compose, then make sure to set a user group so that you don't need to run docker commands with sudo, and then finally switch to server backend before you try to start server: "prefect backend server" and then "prefect server start"

What happens when you do

docker run hello-world

?