Use journald for kernlogs if kern.log not found

On some hosts or sosreports kern.log may be missing so we
fall back to journald for calltrace checking if this is the
case.

hotsos/core/host_helpers/cli/cli.py

@@ -64,6 +64,9 @@ def __init__(self, *args, **kwargs):
 
     def format_journalctl_cmd(self, **kwargs):
         """ Add optional extras to journalctl command. """
+        if kwargs.get("opts"):
+            self.cmd = f"{self.cmd} {kwargs.get('opts')}"
+
         if kwargs.get("unit"):
             self.cmd = f"{self.cmd} --unit {kwargs.get('unit')}"
 
@@ -84,7 +87,13 @@ def __init__(self, *args, **kwargs):
         self.register_hook("pre-exec", self.preformat_sos_journalctl)
 
     def preformat_sos_journalctl(self, **kwargs):
-        self.path = f"journalctl -oshort-iso -D {self.path}"
+        default_opts = '-oshort-iso'
+        if kwargs.get("opts"):
+            self.path = (f"journalctl {default_opts} {kwargs.get('opts')} "
+                         f"-D {self.path}")
+        else:
+            self.path = f"journalctl {default_opts} -D {self.path}"
+
         if kwargs.get("unit"):
             self.path = f"{self.path} --unit {kwargs.get('unit')}"
 

hotsos/core/plugins/kernel/kernlog/calltrace.py

@@ -1,11 +1,14 @@
 import abc
+import os
 import re
 
+from hotsos.core.config import HotSOSConfig
 from hotsos.core.log import log
 from hotsos.core.search import (
     SearchDef,
     SequenceSearchDef,
 )
+from hotsos.core.host_helpers.cli import CLIHelperFile
 from hotsos.core.plugins.kernel.kernlog.common import (
     CallTraceHeuristicBase,
     CallTraceStateBase,
@@ -483,10 +486,19 @@ def __init__(self, *args, **kwargs):
         self.run()
 
     def run(self):
-        for tracetype in self.tracetypes:
-            self.searcher.add(tracetype.searchdef, self.path)
+        path = self.path
+        with CLIHelperFile() as cli:
+            if not os.path.exists(path):
+                path = cli.journalctl(opts='-k')
+            else:
+                if HotSOSConfig.use_all_logs:
+                    path = f"{path}*"
+
+            for tracetype in self.tracetypes:
+                self.searcher.add(tracetype.searchdef, path)
+
+            self.results = self.searcher.run()
 
-        self.results = self.searcher.run()
         for tracetype in self.tracetypes:
             if isinstance(tracetype.searchdef, SequenceSearchDef):
                 results = self.results.find_sequence_sections(

hotsos/core/plugins/kernel/kernlog/common.py

@@ -100,8 +100,11 @@ def __init__(self):
 
     @property
     def path(self):
-        path = os.path.join(HotSOSConfig.data_root, 'var/log/kern.log')
-        if HotSOSConfig.use_all_logs:
-            return f"{path}*"
+        """
+        Return path we want to search. By default we search kern.log but that
+        may not exist e.g. sosreport does not collect it if systemd-journald is
+        running. In that case we need to fallback to using the journal.
 
-        return path
+        @return: path
+        """
+        return os.path.join(HotSOSConfig.data_root, 'var/log/kern.log')

hotsos/core/plugins/kernel/kernlog/events.py

@@ -1,4 +1,8 @@
+import os
+
+from hotsos.core.config import HotSOSConfig
 from hotsos.core.log import log
+from hotsos.core.host_helpers.cli import CLIHelperFile
 from hotsos.core.plugins.kernel.kernlog.common import KernLogBase
 from hotsos.core.search import SearchDef
 
@@ -7,10 +11,18 @@ class KernLogEvents(KernLogBase):
     """ Kern log events info. """
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
-        for event in [self.over_mtu_dropped_packets_search_def]:
-            self.searcher.add(event, self.path)
+        path = self.path
+        with CLIHelperFile() as cli:
+            if not os.path.exists(path):
+                path = cli.journalctl(opts='-k')
+            else:
+                if HotSOSConfig.use_all_logs:
+                    path = f"{path}*"
+
+            for event in [self.over_mtu_dropped_packets_search_def]:
+                self.searcher.add(event, path)
 
-        self.results = self.searcher.run()
+            self.results = self.searcher.run()
 
     @property
     def over_mtu_dropped_packets_search_def(self):