Fix: upgradeutil: refine error handling (bsc#1226147, bsc#1223371)

Getting upgrade seq from remote node may fails for various reasons.
Previous code handles SSH problems gracefully but other problems are
note handled and turn into misleading error messages.

This commit handles those problems in the same way in which SSH problems
are handled: output detail information to debug log and skip upgrading.

crmsh/upgradeutil.py

@@ -102,14 +102,24 @@ def _is_cluster_target_seq_consistent(nodes):
     except (prun.PRunError, crmsh.utils.UserOfHost.UserNotFoundError) as e:
         logger.debug("upgradeutil: get-seq failed: %s", e)
         raise _SkipUpgrade() from None
-    try:
-        return all(
-            CURRENT_UPGRADE_SEQ == _parse_upgrade_seq(result.stdout.strip()) if result.returncode == 0 else False
-            for result in results.values()
-        )
-    except ValueError as e:
-        logger.warning("Remote command '%s' returns unexpected output: %s", cmd, results, exc_info=e)
-        return False
+    ret = True
+    for node, result in results.items():
+        if result.returncode != 0:
+            logger.debug(
+                "upgradeutil: remote command '%s' fails on %s: rc=%s, stdout=%s, stderr=%s",
+                cmd, node, result.returncode, result.stdout, result.stderr,
+            )
+            raise _SkipUpgrade() from None
+        else:
+            try:
+                seq = _parse_upgrade_seq(result.stdout.strip())
+                if CURRENT_UPGRADE_SEQ != seq:
+                    ret = False
+                    logger.debug('seq %s from %s != %s', seq, node, CURRENT_UPGRADE_SEQ)
+            except ValueError as e:
+                ret = False
+                logger.warning("upgradeutil: remote command '%s' returns unexpected output: %s", cmd, results, exc_info=e)
+    return ret
 
 
 def _get_minimal_seq_in_cluster(nodes) -> typing.Tuple[int, int]: