Add hack for Docker cgroups
Docker cgroups are mounted in the wrong place (i.e., inconsistently with
/proc/self/cgroup). This commit adds an undocumented hack for working
around, for now.
Relates
@@ -35,7 +35,6 @@ import java.nio.file.Files;
import java.nio.file.Path;
import java.util.HashMap;
import java.util.List;
-import java.util.Locale;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
@@ -191,6 +190,10 @@ public class OsProbe {
// pattern for lines in /proc/self/cgroup
private static final Pattern CONTROL_GROUP_PATTERN = Pattern.compile("\\d+:([^:,]+(?:,[^:,]+)?):(/.*)");
+ // this property is to support a hack to workaround an issue with Docker containers mounting the cgroups hierarchy inconsistently with
+ // respect to /proc/self/cgroup; for Docker containers this should be set to "/"
+ private static final String CONTROL_GROUPS_HIERARCHY_OVERRIDE = System.getProperty("es.cgroups.hierarchy.override");
+
/**
* A map of the control groups to which the Elasticsearch process belongs. Note that this is a map because the control groups can vary
* from subsystem to subsystem. Additionally, this map can not be cached because a running process can be reclassified.
@@ -209,9 +212,18 @@ public class OsProbe {
// at this point we have captured the subsystems and the control group
final String[] controllers = matcher.group(1).split(",");
for (final String controller : controllers) {
+ if (CONTROL_GROUPS_HIERARCHY_OVERRIDE != null) {
+ /*
+ * Docker violates the relationship between /proc/self/cgroups and the /sys/fs/cgroup hierarchy. It's possible that this
+ * will be fixed in future versions of Docker with cgroup namespaces, but this requires modern kernels. Thus, we provide
+ * an undocumented hack for overriding the control group path. Do not rely on this hack, it will be removed.
+ */
+ controllerMap.put(controller, CONTROL_GROUPS_HIERARCHY_OVERRIDE);
+ } else {
controllerMap.put(controller, matcher.group(2));
}
}
+ }
return controllerMap;
}
