Datonis Edge 5.2 Release Notes
Edge failover to support high availability
Datonis Edge now natively provides failover mechanism. It uses master/slave topology where one instance is active and others are in standby. More than one slaves can be configured for failover. Edge provides failover capability using a lock file from the shared data directory. The shared data directory holds the persistent state. As failover relies on the filesystem lock, the filesystem storing the data directory has to be accessible across instances(using SAN, NFS, …). Refer: https://en.wikipedia.org/wiki/Clustered_file_system. When a first instance starts, if the lock is available, it takes the lock and becomes the master. Whenever a second instance starts, it tries to acquire the lock. As the lock is already held by the master, the instance becomes a slave, in standby mode (not active).
Configuring failover in classic installation
In the install/upgrade scripts (e.g. install_edge_service.sh/upgrade_edge_service.sh), add a new option --datadirpath that will point to the shared data directory across instances e.g. --datadirpath "/shared-vol/datonis-edge-data". After this step, install or upgrade edge service on all instances and edge services will start in failover mode, the first service to start will become master node.
Configuring failover in docker installation
In the Docker command line, edit option --mount to point the source volume to the shared data directory e.g. --mount type=bind,source=/shared-vol/datonis-edge-data,target=/opt/datonis-edge-data. The Docker containers started with shared mounts will configure edge program to run in failover mode. The first started docker container will become master node.
Edge Docker image
Datonis Edge can now be installed in the form of Docker container from this release onward. The Docker image and run command line will be published for subsequent release builds. The Docker image is based on minimal Debian with only necessary dependencies making it lightweight. Docker container supports easy upgrade too. In order to switch to newer release, one has stop old container and run new command line. Container installation inherently eliminates the need for installing dependencies such as particular version of JRE etc. Its also very easy to change default ports of web console to different ports in case default ports are used by some other service.
Fixed handling of 401 Unauthorized error to decline message