HostRegexTableLoadBalancer (Apache Accumulo Server Base 1.9.1 API)

java.lang.Object
- org.apache.accumulo.server.master.balancer.TabletBalancer
- - org.apache.accumulo.server.master.balancer.TableLoadBalancer
  - - org.apache.accumulo.server.master.balancer.HostRegexTableLoadBalancer

All Implemented Interfaces:

ConfigurationObserver
```
public class HostRegexTableLoadBalancer
extends TableLoadBalancer
implements ConfigurationObserver
```
This balancer creates groups of tablet servers using user-provided regular expressions over the tablet server hostnames. Then it delegates to the table balancer to balance the tablets within the resulting group of tablet servers. All tablet servers that do not match a regex are grouped into a default group.
Regex properties for this balancer are specified as:
table.custom.balancer.host.regex.<tablename>=<regex>
Periodically (default 5m) this balancer will check to see if a tablet server is hosting tablets that it should not be according to the regex configuration. If this occurs then the offending tablets will be reassigned. This would cover the case where the configuration is changed and the master is restarted while the tablet servers are up. To change the out of bounds check time period, set the following property:
table.custom.balancer.host.regex.oob.period=5m
(Deprecated) Periodically (default 1m) this balancer will regroup the set of current tablet servers into pools based on regexes applied to the tserver host names. This would cover the case of tservers dying or coming online. To change the host pool check time period, set the following property:
table.custom.balancer.host.regex.pool.check=5m (Deprecated)
Regex matching can be based on either the host name (default) or host ip address. To set this balancer to match the regular expressions to the tablet server IP address, then set the following property:
table.custom.balancer.host.regex.is.ip=true
It's possible that this balancer may create a lot of migrations. To limit the number of migrations that are created during a balance call, set the following property (default 250):
table.custom.balancer.host.regex.concurrent.migrations This balancer can continue balancing even if there are outstanding migrations. To limit the number of outstanding migrations in which this balancer will continue balancing, set the following property (default 0):
table.custom.balancer.host.regex.max.outstanding.migrations

Nested Class Summary
- Nested classes/interfaces inherited from class org.apache.accumulo.server.master.balancer.TabletBalancer
  TabletBalancer.BalancerProblem, TabletBalancer.NoTservers, TabletBalancer.OutstandingMigrations

Field Summary

Fields
Modifier and Type	Field and Description
`protected static String`	`DEFAULT_POOL`
`static String`	`HOST_BALANCER_OOB_CHECK_KEY`
`static String`	`HOST_BALANCER_OUTSTANDING_MIGRATIONS_KEY`
`static String`	`HOST_BALANCER_POOL_RECHECK_KEY` Deprecated.
`static String`	`HOST_BALANCER_PREFIX`
`static String`	`HOST_BALANCER_REGEX_MAX_MIGRATIONS_KEY`
`static String`	`HOST_BALANCER_REGEX_USING_IPS_KEY`
`protected long`	`oobCheckMillis`

Fields inherited from class org.apache.accumulo.server.master.balancer.TabletBalancer
configuration, context, TIME_BETWEEN_BALANCER_WARNINGS

Constructor Summary

Constructors
Constructor and Description

HostRegexTableLoadBalancer()

Constructors
Constructor and Description
`HostRegexTableLoadBalancer()`

Method Summary

All Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`long`	`balance(SortedMap<TServerInstance,TabletServerStatus> current, Set<KeyExtent> migrations, List<TabletMigration> migrationsOut)` Ask the balancer if any migrations are necessary.
`void`	`getAssignments(SortedMap<TServerInstance,TabletServerStatus> current, Map<KeyExtent,TServerInstance> unassigned, Map<KeyExtent,TServerInstance> assignments)` Assign tablets to tablet servers.
`int`	`getMaxConcurrentMigrations()`
`int`	`getMaxMigrations()`
`int`	`getMaxOutstandingMigrations()`
`protected String`	`getNameFromIp(String hostIp)`
`long`	`getOobCheckMillis()`
`protected String`	`getPoolNameForTable(String tableName)` Matches table name against pool names, returns matching pool name or DEFAULT_POOL.
`protected List<String>`	`getPoolNamesForHost(String host)` Matches host against the regexes and returns the matching pool names
`Map<String,Pattern>`	`getPoolNameToRegexPattern()`
`long`	`getPoolRecheckMillis()` Deprecated.
`Map<String,String>`	`getTableIdToTableName()`
`void`	`init(ServerConfigurationFactory conf)` Initialize the TabletBalancer.
`boolean`	`isIpBasedRegex()`
`protected void`	`parseConfiguration(ServerConfiguration conf)` Parse configuration and extract properties
`void`	`propertiesChanged()`
`void`	`propertyChanged(String key)`
`void`	`sessionExpired()`
`protected Map<String,SortedMap<TServerInstance,TabletServerStatus>>`	`splitCurrentByRegex(SortedMap<TServerInstance,TabletServerStatus> current)` Group the set of current tservers by pool name.
`String`	`toString()`

Methods inherited from class org.apache.accumulo.server.master.balancer.TableLoadBalancer
getBalancerForTable, getLoadBalancerClassNameForTable, getTableOperations

Methods inherited from class org.apache.accumulo.server.master.balancer.TabletBalancer
checkMigrationSanity, constraintNotMet, getOnlineTabletsForTable, init, resetBalancerErrors

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

- Field Detail
  - HOST_BALANCER_PREFIX
```
public static final String HOST_BALANCER_PREFIX
```
  - HOST_BALANCER_OOB_CHECK_KEY
```
public static final String HOST_BALANCER_OOB_CHECK_KEY
```
  - HOST_BALANCER_POOL_RECHECK_KEY
```
@Deprecated
public static final String HOST_BALANCER_POOL_RECHECK_KEY
```
    Deprecated.
  - HOST_BALANCER_REGEX_USING_IPS_KEY
```
public static final String HOST_BALANCER_REGEX_USING_IPS_KEY
```
  - HOST_BALANCER_REGEX_MAX_MIGRATIONS_KEY
```
public static final String HOST_BALANCER_REGEX_MAX_MIGRATIONS_KEY
```
  - DEFAULT_POOL
```
protected static final String DEFAULT_POOL
```
    See Also:
    
    Constant Field Values
  - HOST_BALANCER_OUTSTANDING_MIGRATIONS_KEY
```
public static final String HOST_BALANCER_OUTSTANDING_MIGRATIONS_KEY
```
  - oobCheckMillis
```
protected long oobCheckMillis
```
- Constructor Detail
  - HostRegexTableLoadBalancer
```
public HostRegexTableLoadBalancer()
```
- Method Detail
  - splitCurrentByRegex
```
protected Map<String,SortedMap<TServerInstance,TabletServerStatus>> splitCurrentByRegex(SortedMap<TServerInstance,TabletServerStatus> current)
```
    Group the set of current tservers by pool name. Tservers that don't match a regex are put into a default pool. This could be expensive in the terms of the amount of time to recompute the groups, so HOST_BALANCER_POOL_RECHECK_KEY should be specified in the terms of minutes, not seconds or less.
    
    Parameters:
    
    current - map of current tservers
    
    Returns:
    
    current servers grouped by pool name, if not a match it is put into a default pool.
  - getPoolNamesForHost
```
protected List<String> getPoolNamesForHost(String host)
```
    Matches host against the regexes and returns the matching pool names
    
    Parameters:
    
    host - tablet server host
    
    Returns:
    
    pool names, will return default pool if host matches more no regex
  - getNameFromIp
```
protected String getNameFromIp(String hostIp)
                        throws UnknownHostException
```
    Throws:
    
    UnknownHostException
  - getPoolNameForTable
```
protected String getPoolNameForTable(String tableName)
```
    Matches table name against pool names, returns matching pool name or DEFAULT_POOL.
    
    Parameters:
    
    tableName - name of table
    
    Returns:
    
    tablet server pool name (table name or DEFAULT_POOL)
  - parseConfiguration
```
protected void parseConfiguration(ServerConfiguration conf)
```
    Parse configuration and extract properties
    
    Parameters:
    
    conf - server configuration
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - getTableIdToTableName
```
public Map<String,String> getTableIdToTableName()
```
  - getPoolNameToRegexPattern
```
public Map<String,Pattern> getPoolNameToRegexPattern()
```
  - getMaxMigrations
```
public int getMaxMigrations()
```
  - getMaxOutstandingMigrations
```
public int getMaxOutstandingMigrations()
```
  - getOobCheckMillis
```
public long getOobCheckMillis()
```
  - getPoolRecheckMillis
```
@Deprecated
public long getPoolRecheckMillis()
```
    Deprecated.
  - isIpBasedRegex
```
public boolean isIpBasedRegex()
```
  - getMaxConcurrentMigrations
```
public int getMaxConcurrentMigrations()
```
  - init
```
public void init(ServerConfigurationFactory conf)
```
    Description copied from class: TabletBalancer
    
    Initialize the TabletBalancer. This gives the balancer the opportunity to read the configuration.
    
    Overrides:
    
    init in class TabletBalancer
  - getAssignments
```
public void getAssignments(SortedMap<TServerInstance,TabletServerStatus> current,
                           Map<KeyExtent,TServerInstance> unassigned,
                           Map<KeyExtent,TServerInstance> assignments)
```
    Description copied from class: TabletBalancer
    
    Assign tablets to tablet servers. This method is called whenever the master finds tablets that are unassigned.
    
    Overrides:
    
    getAssignments in class TableLoadBalancer
    
    Parameters:
    
    current - The current table-summary state of all the online tablet servers. Read-only. The TabletServerStatus for each server may be null if the tablet server has not yet responded to a recent request for status.
    
    unassigned - A map from unassigned tablet to the last known tablet server. Read-only.
    
    assignments - A map from tablet to assigned server. Write-only.
  - balance
```
public long balance(SortedMap<TServerInstance,TabletServerStatus> current,
                    Set<KeyExtent> migrations,
                    List<TabletMigration> migrationsOut)
```
    Description copied from class: TabletBalancer
    
    Ask the balancer if any migrations are necessary. If the balancer is going to self-abort due to some environmental constraint (e.g. it requires some minimum number of tservers, or a maximum number of outstanding migrations), it should issue a log message to alert operators. The message should be at WARN normally and at ERROR if the balancer knows that the problem can not self correct. It should not issue these messages more than once a minute.
    
    Overrides:
    
    balance in class TableLoadBalancer
    
    Parameters:
    
    current - The current table-summary state of all the online tablet servers. Read-only.
    
    migrations - the current set of migrations. Read-only.
    
    migrationsOut - new migrations to perform; should not contain tablets in the current set of migrations. Write-only.
    
    Returns:
    
    the time, in milliseconds, to wait before re-balancing. This method will not be called when there are unassigned tablets.
  - propertyChanged
```
public void propertyChanged(String key)
```
    Specified by:
    
    propertyChanged in interface ConfigurationObserver
  - propertiesChanged
```
public void propertiesChanged()
```
    Specified by:
    
    propertiesChanged in interface ConfigurationObserver
  - sessionExpired
```
public void sessionExpired()
```
    Specified by:
    
    sessionExpired in interface ConfigurationObserver

Class HostRegexTableLoadBalancer

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.accumulo.server.master.balancer.TabletBalancer

Field Summary

Fields inherited from class org.apache.accumulo.server.master.balancer.TabletBalancer

Constructor Summary

Method Summary

Methods inherited from class org.apache.accumulo.server.master.balancer.TableLoadBalancer

Methods inherited from class org.apache.accumulo.server.master.balancer.TabletBalancer

Methods inherited from class java.lang.Object

Field Detail

HOST_BALANCER_PREFIX

HOST_BALANCER_OOB_CHECK_KEY

HOST_BALANCER_POOL_RECHECK_KEY

HOST_BALANCER_REGEX_USING_IPS_KEY

HOST_BALANCER_REGEX_MAX_MIGRATIONS_KEY

DEFAULT_POOL

HOST_BALANCER_OUTSTANDING_MIGRATIONS_KEY

oobCheckMillis

Constructor Detail

HostRegexTableLoadBalancer

Method Detail

splitCurrentByRegex

getPoolNamesForHost

getNameFromIp

getPoolNameForTable

parseConfiguration

toString

getTableIdToTableName

getPoolNameToRegexPattern

getMaxMigrations

getMaxOutstandingMigrations

getOobCheckMillis

getPoolRecheckMillis

isIpBasedRegex

getMaxConcurrentMigrations

init

getAssignments

balance

propertyChanged

propertiesChanged

sessionExpired