ducktape: improve pid dectection v2

Exclude commands that run `redpanda --version` from pgrep

Signed-off-by: Tyler Rockwood <[email protected]>

tests/rptest/services/redpanda.py

@@ -2891,14 +2891,17 @@ def remove_local_data(self, node):
 
     def redpanda_pid(self, node):
         try:
-            cmd = "pgrep --exact redpanda"
-
-            for p in node.account.ssh_capture(cmd,
-                                              allow_fail=True,
-                                              callback=int,
-                                              timeout_sec=10):
-                return p
-
+            cmd = "pgrep --list-full --exact redpanda"
+            for line in node.account.ssh_capture(cmd,
+                                                 allow_fail=True,
+                                                 timeout_sec=10):
+                # Ignore SSH commands that lookup the version of redpanda
+                # by running `redpanda --version` like in `self.get_version(node)`
+                if "--version" in line:
+                    continue
+                # The pid is listed first, that's all we need
+                return int(line.split()[0])
+            return None
         except (RemoteCommandError, ValueError):
             return None