THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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Provider configuration example
Enables or disables HA Provider and binds strategy and provider together. Alias contains list of Hadoop services (name-nodes in our case: active and standby) grouped into one entity.
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<topology>
<gateway>
...
<provider>
<role>ha</role>
<name>HAProvider</name>
<param>
<name>webhdfs.ha</name>
<value>failover_strategy=BaseStrategy;retryCount=3;timeoutInterval=5000;enabled=true</value>
</param>
</provider>
...
<gateway>
...
<service>
<role>WEBHDFS</role>
<url>machine1.example.com:50070</url>
<url>machine2.example.com:50070</url>
</service>
...
<service>
<role>NAMENODE</role>
<url>machine1.example.com:50070</url>
<url>machine2.example.com:50070</url>
</service>
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</topology> |
Parameters description:
- failover_strategy – indicates how to define active service and contains some configuration parameters. Default value is BaseStrategy. BaseStrategy for failover has following parameters:
- retryCount – indicates how many times knox will ping name-node before knox decides that namenode is down.
- timeoutInterval – interval for connection timeout.
- enabled – indicates whether HAProvider is active or not for service.
Example UML
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autonumber
participant "Deployment\nFactory\n(df)" as df |
Example Code Block
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public class HaBaseStrategyHostMapper implements HostMapper {
@Override
public String resolveInboundHostName(String inboundHost) {
//TODO: implement host resolution here
return null;
}
@Override
public String resolveOutboundHostName(String outboundHost) {
//TODO: implement host resolution here
return null;
}
} |
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public class HaUrlRewriteFunctionDescriptor implements UrlRewriteFunctionDescriptor<HaUrlRewriteFunctionDescriptor> {
public static final String FUNCTION_NAME = "ha-rewrite";
private String configLocation;
@Override
public String name() {
return FUNCTION_NAME;
}
public HaUrlRewriteFunctionDescriptor config( String configLocation ) {
this.configLocation = configLocation;
return this;
}
public String config() {
return configLocation;
}
public String getConfig() {
return config();
}
public void setConfig( String configLocation ) {
config( configLocation );
}
} |
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| language | java |
|---|---|
| title | HaUrlRewriteFunctionProcessor |
| linenumbers | true |
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Please look at the WebHDFS HA section http://knox.apache.org/books/knox-0-5-0/knox-0-5-0.html#WebHDFS
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