RegionServerSnapshotManager (Apache HBase 1.2.12 API)

java.lang.Object
- org.apache.hadoop.hbase.procedure.ProcedureManager
- - org.apache.hadoop.hbase.procedure.RegionServerProcedureManager
  - - org.apache.hadoop.hbase.regionserver.snapshot.RegionServerSnapshotManager

```
@InterfaceAudience.LimitedPrivate(value="Configuration")
@InterfaceStability.Unstable
public class RegionServerSnapshotManager
extends RegionServerProcedureManager
```
This manager class handles the work dealing with snapshots for a HRegionServer.
This provides the mechanism necessary to kick off a online snapshot specific Subprocedure that is responsible for the regions being served by this region server. If any failures occur with the subprocedure, the RegionSeverSnapshotManager's subprocedure handler, ProcedureMember, notifies the master's ProcedureCoordinator to abort all others.
On startup, requires start() to be called.
On shutdown, requires stop(boolean) to be called

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`class`	`RegionServerSnapshotManager.SnapshotSubprocedureBuilder` Build the actual snapshot runner that will do all the 'hard' work
`(package private) static class`	`RegionServerSnapshotManager.SnapshotSubprocedurePool` We use the SnapshotSubprocedurePool, a class specific thread pool instead of `ExecutorService`.

Field Summary

Fields
Modifier and Type	Field and Description
`private static String`	`CONCURENT_SNAPSHOT_TASKS_KEY` Maximum number of snapshot region tasks that can run concurrently
`private static int`	`DEFAULT_CONCURRENT_SNAPSHOT_TASKS`
`private static org.apache.commons.logging.Log`	`LOG`
`private ProcedureMember`	`member`
`private ProcedureMemberRpcs`	`memberRpcs`
`private RegionServerServices`	`rss`
`static int`	`SNAPSHOT_REQUEST_THREADS_DEFAULT` # of threads for snapshotting regions on the rs.
`static String`	`SNAPSHOT_REQUEST_THREADS_KEY` Conf key for number of request threads to start snapshots on regionservers
`private static long`	`SNAPSHOT_REQUEST_WAKE_MILLIS_DEFAULT` Default amount of time to check for errors while regions finish snapshotting
`static String`	`SNAPSHOT_REQUEST_WAKE_MILLIS_KEY` Conf key for millis between checks to see if snapshot completed or if there are errors
`static long`	`SNAPSHOT_TIMEOUT_MILLIS_DEFAULT` Keep threads alive in request pool for max of 300 seconds
`static String`	`SNAPSHOT_TIMEOUT_MILLIS_KEY` Conf key for max time to keep threads in snapshot request pool waiting

Constructor Summary

Constructors
Constructor and Description
`RegionServerSnapshotManager()`
`RegionServerSnapshotManager(org.apache.hadoop.conf.Configuration conf, HRegionServer parent, ProcedureMemberRpcs memberRpc, ProcedureMember procMember)` Exposed for testing.

Method Summary

Methods
Modifier and Type	Method and Description
`Subprocedure`	`buildSubprocedure(org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription snapshot)` If in a running state, creates the specified subprocedure for handling an online snapshot.
`String`	`getProcedureSignature()` Return the unique signature of the procedure.
`private List<Region>`	`getRegionsToSnapshot(org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription snapshot)` Determine if the snapshot should be handled on this server NOTE: This is racy -- the master expects a list of regionservers.
`void`	`initialize(RegionServerServices rss)` Create a default snapshot handler - uses a zookeeper based member controller.
`void`	`start()` Start accepting snapshot requests.
`void`	`stop(boolean force)` Close `this` and all running snapshot tasks

Methods inherited from class org.apache.hadoop.hbase.procedure.ProcedureManager
equals, hashCode

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - LOG
```
private static final org.apache.commons.logging.Log LOG
```
  - CONCURENT_SNAPSHOT_TASKS_KEY
```
private static final String CONCURENT_SNAPSHOT_TASKS_KEY
```
    Maximum number of snapshot region tasks that can run concurrently
    
    See Also:
    Constant Field Values
  - DEFAULT_CONCURRENT_SNAPSHOT_TASKS
```
private static final int DEFAULT_CONCURRENT_SNAPSHOT_TASKS
```
    See Also:
    Constant Field Values
  - SNAPSHOT_REQUEST_THREADS_KEY
```
public static final String SNAPSHOT_REQUEST_THREADS_KEY
```
    Conf key for number of request threads to start snapshots on regionservers
    
    See Also:
    Constant Field Values
  - SNAPSHOT_REQUEST_THREADS_DEFAULT
```
public static final int SNAPSHOT_REQUEST_THREADS_DEFAULT
```
    # of threads for snapshotting regions on the rs.
    
    See Also:
    Constant Field Values
  - SNAPSHOT_TIMEOUT_MILLIS_KEY
```
public static final String SNAPSHOT_TIMEOUT_MILLIS_KEY
```
    Conf key for max time to keep threads in snapshot request pool waiting
    
    See Also:
    Constant Field Values
  - SNAPSHOT_TIMEOUT_MILLIS_DEFAULT
```
public static final long SNAPSHOT_TIMEOUT_MILLIS_DEFAULT
```
    Keep threads alive in request pool for max of 300 seconds
    
    See Also:
    Constant Field Values
  - SNAPSHOT_REQUEST_WAKE_MILLIS_KEY
```
public static final String SNAPSHOT_REQUEST_WAKE_MILLIS_KEY
```
    Conf key for millis between checks to see if snapshot completed or if there are errors
    
    See Also:
    Constant Field Values
  - SNAPSHOT_REQUEST_WAKE_MILLIS_DEFAULT
```
private static final long SNAPSHOT_REQUEST_WAKE_MILLIS_DEFAULT
```
    Default amount of time to check for errors while regions finish snapshotting
    
    See Also:
    Constant Field Values
  - rss
```
private RegionServerServices rss
```
  - memberRpcs
```
private ProcedureMemberRpcs memberRpcs
```
  - member
```
private ProcedureMember member
```
- Constructor Detail
  - RegionServerSnapshotManager
```
RegionServerSnapshotManager(org.apache.hadoop.conf.Configuration conf,
                           HRegionServer parent,
                           ProcedureMemberRpcs memberRpc,
                           ProcedureMember procMember)
```
    Exposed for testing.
    
    Parameters:
    conf - HBase configuration.
    parent - parent running the snapshot handler
    memberRpc - use specified memberRpc instance
    procMember - use specified ProcedureMember
  - RegionServerSnapshotManager
```
public RegionServerSnapshotManager()
```
- Method Detail
  - start
```
public void start()
```
    Start accepting snapshot requests.
    
    Specified by:
    
    start in class RegionServerProcedureManager
  - stop
```
public void stop(boolean force)
          throws IOException
```
    Close this and all running snapshot tasks
    
    Specified by:
    
    stop in class RegionServerProcedureManager
    
    Parameters:
    force - forcefully stop all running tasks
    
    Throws:
    
    IOException
  - buildSubprocedure
```
public Subprocedure buildSubprocedure(org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription snapshot)
```
    If in a running state, creates the specified subprocedure for handling an online snapshot. Because this gets the local list of regions to snapshot and not the set the master had, there is a possibility of a race where regions may be missed. This detected by the master in the snapshot verification step.
    
    Parameters:
    snapshot -
    
    Returns:
    Subprocedure to submit to the ProcedureMemeber.
  - getRegionsToSnapshot
```
private List<Region> getRegionsToSnapshot(org.apache.hadoop.hbase.protobuf.generated.HBaseProtos.SnapshotDescription snapshot)
                                   throws IOException
```
    Determine if the snapshot should be handled on this server NOTE: This is racy -- the master expects a list of regionservers. This means if a region moves somewhere between the calls we'll miss some regions. For example, a region move during a snapshot could result in a region to be skipped or done twice. This is manageable because the MasterSnapshotVerifier will double check the region lists after the online portion of the snapshot completes and will explicitly fail the snapshot.
    
    Parameters:
    snapshot -
    
    Returns:
    the list of online regions. Empty list is returned if no regions are responsible for the given snapshot.
    
    Throws:
    
    IOException
  - initialize
```
public void initialize(RegionServerServices rss)
                throws org.apache.zookeeper.KeeperException
```
    Create a default snapshot handler - uses a zookeeper based member controller.
    
    Specified by:
    
    initialize in class RegionServerProcedureManager
    
    Parameters:
    rss - region server running the handler
    
    Throws:
    
    org.apache.zookeeper.KeeperException - if the zookeeper cluster cannot be reached
  - getProcedureSignature
```
public String getProcedureSignature()
```
    Description copied from class: ProcedureManager
    
    Return the unique signature of the procedure. This signature uniquely identifies the procedure. By default, this signature is the string used in the procedure controller (i.e., the root ZK node name for the procedure)
    
    Specified by:
    
    getProcedureSignature in class ProcedureManager

Class RegionServerSnapshotManager

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class org.apache.hadoop.hbase.procedure.ProcedureManager

Methods inherited from class java.lang.Object

Field Detail

LOG

CONCURENT_SNAPSHOT_TASKS_KEY

DEFAULT_CONCURRENT_SNAPSHOT_TASKS

SNAPSHOT_REQUEST_THREADS_KEY

SNAPSHOT_REQUEST_THREADS_DEFAULT

SNAPSHOT_TIMEOUT_MILLIS_KEY

SNAPSHOT_TIMEOUT_MILLIS_DEFAULT

SNAPSHOT_REQUEST_WAKE_MILLIS_KEY

SNAPSHOT_REQUEST_WAKE_MILLIS_DEFAULT

rss

memberRpcs

member

Constructor Detail

RegionServerSnapshotManager

RegionServerSnapshotManager

Method Detail

start

stop

buildSubprocedure

getRegionsToSnapshot

initialize

getProcedureSignature