I have setup have 2 nodes of MariaDB 10.0 Galera cluster running on both private IPs of 192.168.2.51 and 192.168.2.52. I'm about to try connecting to the cluster using MariaDB's JDBC Client (org.mariadb.jdbc.Driver) provided by MariaDB's website.
It worked with the regular url like: "jdbc:mariadb://192.168.2.51:3306,192.168.2.52:3306/dbname".
But what I am trying to achieve is the possibility with the MySQL JDBC Driver, with url like: "jdbc:mysql://192.168.2.51,192.168.2.52/dbname?autoReconnect=true&autoReconnectForPools=true&failoverReadonly=false&roundRobinLoadBalance=true"
I have compared the properties stated in MariaDB (https://mariadb.com/kb/en/about-the-mariadb-java-client/) and MySQL (http://dev.mysql.com/doc/refman/5.5/en/connector-j-reference-configuration-properties.html). For the MariaDB JDBC Client, it doesn't seem to have properties that deal with loadbalance or autoReconnect.
So my question is:
Is there a right recommended way to connect (with loadbalance and failover capability) to MariaDB Galera through the MariaDB JDBC Driver or should I fall back to MySQL's ConnectorJ and how compatible is ConnectorJ with regards to MariaDB Galera cluster?
Thank you.
There is no loadbalance or failover capability in MariaDB JDBC . Even the multiple endpoint feature you used is not documented and is experimental. ConnectorJ loadbalancing should work fine, because to it, MariaDB Galera is just instances of regular MySQL.
You just use failover.
From what I observe, jdbc:mariadb:failover in mariadb connector equals jdbc:mysql:loadbalance in mysql connector;
and jdbc:mariadb:sequential in mariadb equals jdbc:mysql:failover in mysql.
This is a bit confusing.
In Mariadb, even the word is failover, the read/write load is actually spread across all nodes. I prefer to use sequential so that the connections are always to one node, which is more reliable in some cases, such as with galera multi-master cluster.
https://mariadb.com/kb/en/library/about-mariadb-connector-j/
Related
The Goal
I need to query a Redshift cluster from my golang application. The cluster is not available for public, so I want to use SSH to access the said cluster via bastion host.
Status Quo
I have an AWS Redshift cluster in a private VPC, with inbound rules to not allow any traffic from the internet, but tcp 22;
There's a bastion (which can connect to the cluster), so fowarding a port and using rsql works perfectly fine from the terminal;
I use ODBC, and the official ODBC driver from AWS;
In golang application, I use the following db implementation of the ODBC https://github.com/alexbrainman/odbc;
I can't use Devart's Redshift ODBC driver;
I can't use JDBC;
MacOS/Unix.
The Problem
The problem is pretty much trivial. When cluster is available for public and accessible from the internet, the alexbramain's library does it job. However, when the cluster is behind the wall, that's when problems kick in.
The code of the library is translated into C (system calls), I can't really debug it. While, with mysql, e.g., it's possible to register your custom dialer, it doesn't seem to be a case with ODBC.
Even when the tunnel is active, providing an ODBC DSN to the local host for some reason doesn't work. The SQLRETURN is always -1 (api/zapi_unix.go).
The Question
Did someone have such experience? How did you resolve a problem of accessing the cluster from the internet via a go app?
Thank you!
Is it possible to use multiple hive servers in the jdbc URL?
jdbc:hive2://ip1:10000,ip2:10000/;transportMode=http;
Basically I want an Active Passive kind of setup and if the first server is not available i want to use the second one. I don't want to go through zk setup as load balancing is not required.
I am using hive over socks proxy.
Zookeeper is for failover also, not just load balancing, and that's how you can get a highly available HiveServer connection
To provide high availability or load balancing for HiveServer2, Hive provides a function called dynamic service discovery where multiple HiveServer2 instances can register themselves with Zookeeper
https://www.ibm.com/support/knowledgecenter/en/SSCRJT_5.0.1/com.ibm.swg.im.bigsql.admin.doc/doc/admin_HA_HiveS2.html
You should be using Zookeeper already for a highly available namenode
I am following this guide on Hadoop/FIWARE-Cosmos and I have a question about the Hive part.
I can access the old cluster’s (cosmos.lab.fiware.org) headnode through SSH, but I cannot do it for the new cluster. I tried both storage.cosmos.lab.fiware.org and computing.cosmos.lab.fiware.org and failed to connect.
My intention in trying to connect via SSH was to test Hive queries on our data through the Hive CLI. After failing to do so, I checked and was able to connect to the 10000 port of computing.cosmos.lab.fiware.org with telnet. I guess Hive is served through that port. Is this the only way we can use Hive in the new cluster?
The new pair of clusters have not enabled the ssh access. This is because users tend to install a lot of stuff (even not related with Big Data) in the “old” cluster, which had the ssh access enabled as you mention. So, the new pair of clusters are intended to be used only through the APIs exposed: WebHDFS for data I/O and Tidoop for MapReduce.
Being said that, a Hive Server is running as well and it should be exposing a remote service in the 10000 port as you mention as well. I say “it should be” because it is running an experimental authenticator module based in OAuth2 as WebHDFS and Tidoop do. Theoretically, connecting to that port from a Hive client is as easy as using your Cosmos username and a valid token (the same you are using for WebHDFS and/or Tidoop).
And what about a Hive remote client? Well, this is something your application should implement. Anyway, I have uploaded some implementation examples in the Cosmos repo. For instance:
https://github.com/telefonicaid/fiware-cosmos/tree/develop/resources/java/hiveserver2-client
I have 2 nodes sql server 2012 installed and clustered and configured Always On feature with Synchronized option.
Clustername: Cluster1
node 1 name: db1
node 2 name: db2
SQL Availability group name: AVG1 has 2 IP address( 10.X.30.7 and 10.X.31.7)
N0w i need to connect to the database from the application( using tomcat 7). Could you please let me know the jdbc syntax how to connect to the database ?
What would be the SQL server name i have to mention in my application?
And Could you please share JDBC connection example string with the above data?
Let me know for more details
So, if you have created an availability group listener, then that is the server name that you have to reference as this is the name that the windows cluster keeps online as a resource so that the servername never changes no matter what replica the availability group is running on.
The connection string also depends on what port you set the listener up on too, but I'm going to assume that you are using a default instance, your listener is called AG-Listener and it is running on port 1433:
jdbc:sqlserver://AG-Listener:1433;databaseName=YourDB;user=MyUserName;password=*****;
You can find many more examples of JDBC connection strings here:
Building the Connection URL
I have a multi tier application that want to use a RAC to improve the availability of the server.
What we have now is, the client side sending a transaction data to the server side through a webservice. At client level, we need to specify the url address (IP address) as a path to send a data.
As for now, there are 2 oracle instance installed as a RAC at a server.
1. 133.38.52.101
2. 133.38.52.102
Both of the server are connect to same Oracle Database (SAN storage).
Let say, the client side is pointing to .101. Suddenly the .101 machine is down, how can I possible to use the .102 without changing the point URL at the client side. Is there any configuration can be done at RAC or Windows Server 2008 for this type of problem?
Use a load balancer between client machine and application server machines.
Use Oracle's transparent application failover functionality in OCI to achieve redundancy and load balancing between application server machines and RAC instances. DML transactions will be rolled back but selects will be transparently failed over.