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https://issues.apache.org/jira/browse/PHOENIX-3654?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16098587#comment-16098587
]
ASF GitHub Bot commented on PHOENIX-3654:
-----------------------------------------
Github user joshelser commented on a diff in the pull request:
https://github.com/apache/phoenix/pull/236#discussion_r129068996
--- Diff:
phoenix-load-balancer/src/main/java/org/apache/phoenix/queryserver/register/ZookeeperRegistry.java
---
@@ -0,0 +1,72 @@
+/**
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.phoenix.queryserver.register;
+
+
+import com.google.common.net.HostAndPort;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.curator.framework.CuratorFramework;
+import org.apache.curator.framework.CuratorFrameworkFactory;
+import org.apache.curator.retry.ExponentialBackoffRetry;
+import org.apache.curator.utils.CloseableUtils;
+import org.apache.phoenix.loadbalancer.service.LoadBalanceZookeeperConf;
+import org.apache.phoenix.queryserver.server.QueryServer;
+import org.apache.zookeeper.CreateMode;
+import org.apache.zookeeper.data.Stat;
+
+import java.nio.charset.StandardCharsets;
+
+
+public class ZookeeperRegistry implements Registry {
+
+ protected static final Log LOG = LogFactory.getLog(QueryServer.class);
+ private CuratorFramework client;
+
+ public ZookeeperRegistry(){}
+
+ @Override
+ public void registerServer(LoadBalanceZookeeperConf configuration,
int pqsPort,
+ String zookeeperConnectString, String
pqsHost)
+ throws Exception {
+
+ this.client =
CuratorFrameworkFactory.newClient(zookeeperConnectString,
+ new ExponentialBackoffRetry(1000,10));
+ this.client.start();
+ HostAndPort hostAndPort = HostAndPort.fromParts(pqsHost,pqsPort);
+ String path = configuration.getFullPathToNode(hostAndPort);
+ String node = hostAndPort.toString();
+
this.client.create().creatingParentsIfNeeded().withMode(CreateMode.EPHEMERAL).forPath(path
+ ,node.getBytes(StandardCharsets.UTF_8));
+ Stat stat =
this.client.setACL().withACL(configuration.getAcls()).forPath(path);
+ if (stat != null) {
+ LOG.info(" node created with right ACL");
+ }
+ else {
+ LOG.error("could not create node with right ACL. So, system
would exit now.");
+ System.exit(-1);
--- End diff --
Calling `System.exit(-1)` is pretty brutal for anyone trying to integrate
with your software :)
Throwing a RuntimeException would be nicer.
> Load Balancer for thin client
> -----------------------------
>
> Key: PHOENIX-3654
> URL: https://issues.apache.org/jira/browse/PHOENIX-3654
> Project: Phoenix
> Issue Type: New Feature
> Affects Versions: 4.8.0
> Environment: Linux 3.13.0-107-generic kernel, v4.9.0-HBase-0.98
> Reporter: Rahul Shrivastava
> Assignee: Rahul Shrivastava
> Attachments: LoadBalancerDesign.pdf, Loadbalancer.patch
>
> Original Estimate: 240h
> Remaining Estimate: 240h
>
> We have been having internal discussion on load balancer for thin client for
> PQS. The general consensus we have is to have an embedded load balancer with
> the thin client instead of using external load balancer such as haproxy. The
> idea is to not to have another layer between client and PQS. This reduces
> operational cost for system, which currently leads to delay in executing
> projects.
> But this also comes with challenge of having an embedded load balancer which
> can maintain sticky sessions, do fair load balancing knowing the load
> downstream of PQS server. In addition, load balancer needs to know location
> of multiple PQS server. Now, the thin client needs to keep track of PQS
> servers via zookeeper ( or other means).
> In the new design, the client ( PQS client) , it is proposed to have an
> embedded load balancer.
> Where will the load Balancer sit ?
> The load load balancer will embedded within the app server client.
> How will the load balancer work ?
> Load balancer will contact zookeeper to get location of PQS. In this case,
> PQS needs to register to ZK itself once it comes online. Zookeeper location
> is in hbase-site.xml. It will maintain a small cache of connection to the
> PQS. When a request comes in, it will check for an open connection from the
> cache.
> How will load balancer know load on PQS ?
> To start with, it will pick a random open connection to PQS. This means that
> load balancer does not know PQS load. Later , we can augment the code so that
> thin client can receive load info from PQS and make intelligent decisions.
> How will load balancer maintain sticky sessions ?
> While we still need to investigate how to implement sticky sessions. We can
> look for some open source implementation for the same.
> How will PQS register itself to service locator ?
> PQS will have location of zookeeper in hbase-site.xml and it would register
> itself to the zookeeper. Thin client will find out PQS location using
> zookeeper.
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