Package org.apache.catalina.tribes.membership.cloud

Class DNSMembershipProvider

java.lang.Object

org.apache.catalina.tribes.membership.MembershipProviderBase

org.apache.catalina.tribes.membership.cloud.CloudMembershipProvider

org.apache.catalina.tribes.membership.cloud.DNSMembershipProvider

All Implemented Interfaces:

ChannelListener, Heartbeat, MembershipProvider

public class DNSMembershipProvider
extends CloudMembershipProvider

A MembershipProvider that uses DNS to retrieve the members of a cluster.

Configuration example for Kubernetes

server.xml

 
 <Server ...

   <Service ...

     <Engine ...

       <Host ...

         <Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster">
           <Channel className="org.apache.catalina.tribes.group.GroupChannel">
             <Membership className="org.apache.catalina.tribes.membership.cloud.CloudMembershipService"
                 membershipProviderClassName="org.apache.catalina.tribes.membership.cloud.DNSMembershipProvider"/>
           </Channel>
         </Cluster>
         ...
  
  

dns-membership-service.yml

 
 apiVersion: v1
 kind: Service
 metadata:
   annotations:
     service.alpha.kubernetes.io/tolerate-unready-endpoints: "true"
     description: "The service for tomcat cluster membership."
   name: my-tomcat-app-membership
 spec:
   clusterIP: None
   ports:
   - name: membership
     port: 8888
   selector:
     app: my-tomcat-app
 
 

Environment variable configuration
DNS_MEMBERSHIP_SERVICE_NAME=my-tomcat-app-membership

Field Summary

Fields inherited from class org.apache.catalina.tribes.membership.cloud.CloudMembershipProvider

connectionTimeout, CUSTOM_ENV_PREFIX, expirationTime, headers, localIp, md5, port, readTimeout, sm, startTime, streamProvider, url

Fields inherited from class org.apache.catalina.tribes.membership.MembershipProviderBase

executor, membership, membershipListener, service

Constructor Summary

Constructors

Constructor	Description
DNSMembershipProvider()

Method Summary

Modifier and Type	Method	Description
boolean	accept(Serializable msg, Member sender)	Invoked by the channel to determine if the listener will process this message or not.
protected Member[]	fetchMembers()	Fetch current cluster members from the cloud orchestration.
void	start(int level)	Start the membership provider.
boolean	stop(int level)	Stop the membership provider.

Methods inherited from class org.apache.catalina.tribes.membership.cloud.CloudMembershipProvider

getEnv, getNamespace, heartbeat, init, messageReceived, updateMember

Methods inherited from class org.apache.catalina.tribes.membership.MembershipProviderBase

getMember, getMembers, hasMembers, setMembershipListener, setMembershipService

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

DNSMembershipProvider

public DNSMembershipProvider()

Method Details

start

public void start(int level)
           throws Exception

Description copied from interface: MembershipProvider

Start the membership provider.

Specified by:

start in interface MembershipProvider

Overrides:

start in class CloudMembershipProvider

Parameters:

level - the readiness level
Channel.DEFAULT - will start all services
Channel.MBR_RX_SEQ - starts the membership receiver
Channel.MBR_TX_SEQ - starts the membership broadcaster

Throws:

Exception - if an error occurs

stop

public boolean stop(int level)
             throws Exception

Description copied from interface: MembershipProvider

Stop the membership provider.

Specified by:

stop in interface MembershipProvider

Overrides:

stop in class CloudMembershipProvider

Parameters:

level - the readiness level
Channel.DEFAULT - will stop all services
Channel.MBR_RX_SEQ - stops the membership receiver
Channel.MBR_TX_SEQ - stops the membership broadcaster

Returns:

true if successful

Throws:

Exception - if an error occurs

fetchMembers

protected Member[] fetchMembers()

Description copied from class: CloudMembershipProvider

Fetch current cluster members from the cloud orchestration.

Specified by:

fetchMembers in class CloudMembershipProvider

Returns:

the member array

accept

public boolean accept(Serializable msg,
 Member sender)

Description copied from interface: ChannelListener

Invoked by the channel to determine if the listener will process this message or not.

Specified by:

accept in interface ChannelListener

Overrides:

accept in class CloudMembershipProvider

Parameters:

msg - Serializable

sender - Member

Returns:

boolean