Slurm Job Fails Due to Missing SSL Certificates When Creating Cluster using dask-gateway-server

When I created a cluster on HPC using Slurm and dask-gateway-server, I encountered a problem. My understanding of the running process is as follows: when dask-gateway-server receives the new_cluster command from the client, it converts the command into an `sbatch` command. I have edited the `dask_gateway_server/backends/jobqueue/slurm.py` file and print the variables cmd, env, and script in `get_submit_cmd_env_stdin`, the output are as follows:

cmd

```

['/usr/bin/sbatch', '--parsable', '--job-name=dask-gateway', '--chdir=/home/dask/.dask-gateway/014af831909a4d8ab6b900b03fc9598d', '--output=/home/dask/.dask-gateway/014af831909a4d8ab6b900b03fc9598d/dask-scheduler-014af831909a4d8ab6b900b03fc9598d.log', '--cpus-per-task=2', '--mem=4096M', '--export=DASK_DISTRIBUTED__COMM__REQUIRE_ENCRYPTION,DASK_DISTRIBUTED__COMM__TLS__CA_FILE,DASK_DISTRIBUTED__COMM__TLS__SCHEDULER__CERT,DASK_DISTRIBUTED__COMM__TLS__SCHEDULER__KEY,DASK_GATEWAY_API_TOKEN,DASK_GATEWAY_API_URL,DASK_GATEWAY_CLUSTER_NAME']

```

env

```

{'DASK_DISTRIBUTED__COMM__REQUIRE_ENCRYPTION': 'True', 'DASK_GATEWAY_API_URL': '', 'DASK_GATEWAY_API_TOKEN': '3497e6f64a16424eae3b5545f151fb79', 'DASK_GATEWAY_CLUSTER_NAME': '014af831909a4d8ab6b900b03fc9598d', 'DASK_DISTRIBUTED__COMM__TLS__CA_FILE': '/home/dask/.dask-gateway/014af831909a4d8ab6b900b03fc9598d/dask.crt', 'DASK_DISTRIBUTED__COMM__TLS__SCHEDULER__KEY': '/home/dask/.dask-gateway/014af831909a4d8ab6b900b03fc9598d/dask.pem', 'DASK_DISTRIBUTED__COMM__TLS__SCHEDULER__CERT': '/home/dask/.dask-gateway/014af831909a4d8ab6b900b03fc9598d/dask.crt'}

```

script

```
#!/bin/sh
source /opt/dask-gateway/anaconda/bin/activate /opt/dask
dask-scheduler --protocol tls --port 0 --host 0.0.0.0 --dashboard-address 0.0.0.0:0 --preload dask_gateway.scheduler_preload --dg-api-address 0.0.0.0:0 --dg-heartbeat-period 15 --dg-adaptive-period 3.0 --dg-idle-timeout 0.0

```

When the Slurm node receives this command and begins execution, if the non-edge node receives the Slurm Job, it will try to find the dask.crt and dask.pem files that appear in the environment variables above, but these files do not exist on this node. The Slurm task will fail and the error message is as follows:

```
2023-05-29 17:09:58,047 - distributed.preloading - INFO - Import preload module: dask_gateway.scheduler_preload
/opt/dask/lib/python3.10/site-packages/distributed/cli/dask_scheduler.py:140: FutureWarning: dask-scheduler is deprecated and will be removed in a future release; use `dask scheduler` instead
warnings.warn(
2023-05-29 17:09:58,049 - distributed.scheduler - INFO - -----------------------------------------------
2023-05-29 17:09:58,050 - distributed.preloading - INFO - Creating preload: dask_gateway.scheduler_preload
2023-05-29 17:09:58,050 - distributed.preloading - INFO - Import preload module: dask_gateway.scheduler_preload
2023-05-29 17:09:58,050 - distributed.scheduler - INFO - End scheduler
Traceback (most recent call last):
File "/opt/dask/bin/dask-scheduler", line 8, in
sys.exit(main())
File "/opt/dask/lib/python3.10/site-packages/click/core.py", line 1130, in __call__
return self.main(*args, **kwargs)
File "/opt/dask/lib/python3.10/site-packages/click/core.py", line 1055, in main
rv = self.invoke(ctx)
File "/opt/dask/lib/python3.10/site-packages/click/core.py", line 1404, in invoke
return ctx.invoke(self.callback, **ctx.params)
File "/opt/dask/lib/python3.10/site-packages/click/core.py", line 760, in invoke
return __callback(*args, **kwargs)
File "/opt/dask/lib/python3.10/site-packages/distributed/cli/dask_scheduler.py", line 249, in main
asyncio.run(run())
File "/opt/dask/lib/python3.10/asyncio/runners.py", line 44, in run
return loop.run_until_complete(main)
File "/opt/dask/lib/python3.10/asyncio/base_events.py", line 649, in run_until_complete
return future.result()
File "/opt/dask/lib/python3.10/site-packages/distributed/cli/dask_scheduler.py", line 209, in run
scheduler = Scheduler(
File "/opt/dask/lib/python3.10/site-packages/distributed/scheduler.py", line 3464, in __init__
self.connection_args = self.security.get_connection_args("scheduler")
File "/opt/dask/lib/python3.10/site-packages/distributed/security.py", line 342, in get_connection_args
"ssl_context": self._get_tls_context(tls, ssl.Purpose.SERVER_AUTH),
File "/opt/dask/lib/python3.10/site-packages/distributed/security.py", line 299, in _get_tls_context
ctx = ssl.create_default_context(purpose=purpose, cafile=ca)
File "/opt/dask/lib/python3.10/ssl.py", line 766, in create_default_context
context.load_verify_locations(cafile, capath, cadata)
FileNotFoundError: [Errno 2] No such file or directory

```
@jcrist @consideRatio @TomAugspurger @jacobtomlinson @martindurant