High Availability
A high availability installation consists of having two or more installations of Deyel connected to each other, sharing the same database. Each of these installations is identified as a member and they all form a cluster, which is necessary to have a high availability installation.
Each member of the cluster includes internally a software that allows a high availability operation called Hazelcast. To make these members know each other and guarantee high availability, it is necessary to carry out a certain configuration.
Steps for the Configuration of each Member
Step 1: Activate the “HAZELCAST_USE_XML” property in the shared database
This property allows the configuration of Hazelcast in XML mode to specify the different ways of connecting among members.
To activate the property, it is necessary to include it in the “property_value” table using the following sentence:
insert into property_value (CD_PROPERTY, CD_LEVEL, CD_LEVEL_VALUE, DS_VALUE, CD_USER_STORE, DT_STORE, CD_USER_UPDATE, DT_LAST_UPDATE) values('HAZELCAST_USE_XML','OWNER','0','true',NULL,NULL,NULL,NULL);
Step 2: Configure the Hazelcast XML file
Within the installation of each cluster member, the XML file “hazelcast.xml” located in the path <miInstalacion>\ WEB-INF\classes\ should be configured.
Its configuration consists of:
•Set the name of the cluster for each member to connect to, optionally the password can also be specified.
•Configure member discovery on the network. There are several ways to do this, such as multicast, TPC-IP, etc. You can choose the most convenient way for each installation, following the recommendations of the Hazelcast guide on their site
https://docs.hazelcast.org/docs/3.11.7/manual/html-single/index.html#setting-up-clusters
Step 3: Restart
Once configured, members should be restarted so that they can connect to each other. To verify this, the application servers log should be shown and the connection of members should be verified.
Each member is considered to be installed on a full application server.
Example: In Tomcat, the cluster can be shown in the "catalina" log, visualizing the connection of 6 members.
For more details of Hazelcast configurations, show the documentation of its site https://docs.hazelcast.org/docs/3.11.7/manual/html-single/index.html.
