/// <exception cref="System.IO.IOException"/>
/// <exception cref="Org.Apache.Hadoop.HA.ServiceFailedException"/>
private int Failover(CommandLine cmd)
{
bool forceFence = cmd.HasOption(Forcefence);
bool forceActive = cmd.HasOption(Forceactive);
int numOpts = cmd.GetOptions() == null ? 0 : cmd.GetOptions().Length;
string[] args = cmd.GetArgs();
if (numOpts > 3 || args.Length != 2)
{
errOut.WriteLine("failover: incorrect arguments");
PrintUsage(errOut, "-failover");
return(-1);
}
HAServiceTarget fromNode = ResolveTarget(args[0]);
HAServiceTarget toNode = ResolveTarget(args[1]);
// Check that auto-failover is consistently configured for both nodes.
Preconditions.CheckState(fromNode.IsAutoFailoverEnabled() == toNode.IsAutoFailoverEnabled
(), "Inconsistent auto-failover configs between %s and %s!", fromNode, toNode);
if (fromNode.IsAutoFailoverEnabled())
{
if (forceFence || forceActive)
{
// -forceActive doesn't make sense with auto-HA, since, if the node
// is not healthy, then its ZKFC will immediately quit the election
// again the next time a health check runs.
//
// -forceFence doesn't seem to have any real use cases with auto-HA
// so it isn't implemented.
errOut.WriteLine(Forcefence + " and " + Forceactive + " flags not " + "supported with auto-failover enabled."
);
return(-1);
}
try
{
return(GracefulFailoverThroughZKFCs(toNode));
}
catch (NotSupportedException e)
{
errOut.WriteLine("Failover command is not supported with " + "auto-failover enabled: "
+ e.GetLocalizedMessage());
return(-1);
}
}
FailoverController fc = new FailoverController(GetConf(), requestSource);
try
{
fc.Failover(fromNode, toNode, forceFence, forceActive);
@out.WriteLine("Failover from " + args[0] + " to " + args[1] + " successful");
}
catch (FailoverFailedException ffe)
{
errOut.WriteLine("Failover failed: " + ffe.GetLocalizedMessage());
return(-1);
}
return(0);
}
/// <summary>
/// Ensure that we are allowed to manually manage the HA state of the target
/// service.
/// </summary>
/// <remarks>
/// Ensure that we are allowed to manually manage the HA state of the target
/// service. If automatic failover is configured, then the automatic
/// failover controllers should be doing state management, and it is generally
/// an error to use the HAAdmin command line to do so.
/// </remarks>
/// <param name="target">the target to check</param>
/// <returns>true if manual state management is allowed</returns>
private bool CheckManualStateManagementOK(HAServiceTarget target)
{
if (target.IsAutoFailoverEnabled())
{
if (requestSource != HAServiceProtocol.RequestSource.RequestByUserForced)
{
errOut.WriteLine("Automatic failover is enabled for " + target + "\n" + "Refusing to manually manage HA state, since it may cause\n"
+ "a split-brain scenario or other incorrect state.\n" + "If you are very sure you know what you are doing, please \n"
+ "specify the --" + Forcemanual + " flag.");
return(false);
}
else
{
Log.Warn("Proceeding with manual HA state management even though\n" + "automatic failover is enabled for "
+ target);
return(true);
}
}
return(true);
}