[BUG] Without use_master_when_local=True minion ignores master parameter

In this config:

file_client: local
master: 1.2.3.4
use_master_when_local: False

minion is tries to connect to 127.0.0.1:

21:19:31 - salt.minion:245 - DEBUG - Master URI: tcp://127.0.0.1:4506

But if I set use_master_when_local: True minion starts to connect to the master:

21:22:58 - salt.transport.zeromq:258 - DEBUG - Connecting the Minion to the Master URI (for the return server): tcp://1.2.3.4:4506
21:22:58 - salt.transport.zeromq:1300 - DEBUG - Trying to connect to: tcp://1.2.3.4:4506

[rrrix]

Just ran into this, but in an even worse way that killed my dev server 😦

With this config:

# Masterless Minion
master_type: disable
file_client: local

file_roots:
  base:
    - /srv/salt/state
pillar_roots:
  base:
    - /srv/salt/pillar

fileserver_backend:
  - roots

metadata_server_grains: True

And then I (accidentally) forgot to disable the salt-minion systemd service while using my masterless minion. My /var/log/salt/minion file quickly filled up my ~30GB root disk in about 2.5 hours.

# ls -lh /var/log/salt/minion
-rw-r----- 1 root root 29G Sep 20 18:44 /var/log/salt/minion

Repeated ad-infinitum:

2022-09-20 16:16:36,397 [salt.minion      :534 ][WARNING ][627] Master is set to disable, skipping connection
2022-09-20 16:16:36,397 [salt.minion      :1160][CRITICAL][627] Unexpected error while connecting to salt
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/salt/minion.py", line 1134, in _connect_minion
    yield minion.connect_master(failed=failed)
  File "/usr/lib/python3/dist-packages/salt/ext/tornado/gen.py", line 1056, in run
    value = future.result()
  File "/usr/lib/python3/dist-packages/salt/ext/tornado/concurrent.py", line 249, in result
    raise_exc_info(self._exc_info)
  File "<string>", line 4, in raise_exc_info
  File "/usr/lib/python3/dist-packages/salt/ext/tornado/gen.py", line 1070, in run
    yielded = self.gen.send(value)
  File "/usr/lib/python3/dist-packages/salt/minion.py", line 1365, in connect_master
    self.req_channel = salt.transport.client.AsyncReqChannel.factory(
  File "/usr/lib/python3/dist-packages/salt/transport/client.py", line 83, in factory
    return salt.channel.client.AsyncReqChannel.factory(opts, **kwargs)
  File "/usr/lib/python3/dist-packages/salt/channel/client.py", line 127, in factory
    auth = salt.crypt.AsyncAuth(opts, io_loop=io_loop)
  File "/usr/lib/python3/dist-packages/salt/crypt.py", line 506, in __new__
    key = cls.__key(opts)
  File "/usr/lib/python3/dist-packages/salt/crypt.py", line 525, in __key
    opts["master_uri"],  # master ID
KeyError: 'master_uri'

~20 million exceptions between 2022-09-20 16:16:36,385 (first log entry) and 2022-09-20 18:44:12,741 (last log entry) - about 2.5 hours.

# grep 'opts\["master_uri"\]' /var/log/salt/minion | wc -l
20623786

[rrrix]

This works:

diff --git a/salt/minion.py b/salt/minion.py
index cecc4f4adf..40a1584f06 100644
--- a/salt/minion.py
+++ b/salt/minion.py
@@ -533,7 +533,7 @@ class MinionBase:
         if opts["master_type"] == "disable":
             log.warning("Master is set to disable, skipping connection")
             self.connected = False
-            raise salt.ext.tornado.gen.Return((None, None))
+            raise SaltSystemExit(1, "Master Connection Disabled")
 
         # Run masters discovery over SSDP. This may modify the whole configuration,
         # depending of the networking and sets of masters.

As far as I can figure, I don’t think master_type: disable was actually ever tested - at least not thoroughly. The previous line raise salt.ext.tornado.gen.Return((None, None)) has literally no effect, given that the function is always returned as a coroutine generator, which itself lives inside an infinite loop.

I’m looking a little bit more to see what test cases might look like for a PR, but I’m afraid I might have to build out a non-trivial amount of code to test if any Salt daemon should self-exit, given a certain configuration (such as this).

This patch also may not be viable for a scenario such as:

• A master is configured
• The minion has a valid connection (Approved keys) to the master
• A user wants to use salt-call with a temporary configuration of master_type: disable, via a Saltfile for example, (instead of, for some reason, using --local)