Azure Network Load Balancing & Failover: Install the SafeKit farm.safe Module

High Availability Quick Installation Guide for Azure

This guide explains how to set up a farm cluster for Azure using SafeKit, ensuring network load balancing and automatic failover.

For help, you can use SafeKit AI 🤖.

1. Overview

• Architecture: Implements a scalable, multi-node load-balanced farm with a virtual IP address.
• High Availability: Features automatic health monitoring and seamless failover to ensure service continuity.

2. Installation

• Software: Install the SafeKit engine on all servers.
• Module: Download the pre-configured farm.safe application module.

3. Configuration

• Web Console: Configure the Azure farm cluster.
• Monitoring: Start monitoring and protecting the Azure application.

SafeKit High Availability Limitations

Why a replication of a few Tera-bytes?

Resynchronization time after a failure (step 3)

• 1 Gb/s network ≈ 3 Hours for 1 Tera-bytes.
• 10 Gb/s network ≈ 1 Hour for 1 Tera-bytes or less depending on disk write performances.

Alternative

• For a large volume of data, use external shared storage.
• More expensive, more complex.

Why a replication < 1,000,000 files?

• Resynchronization time performance after a failure (step 3).
• Time to check each file between both nodes.

Alternative

• Put the many files to replicate in a virtual hard disk / virtual machine.
• Only the files representing the virtual hard disk / virtual machine will be replicated and resynchronized in this case.

Why a failover ≤ 32 replicated VMs?

• Each VM runs in an independent mirror module.
• Maximum of 32 mirror modules running on the same cluster.

Alternative

• Use an external shared storage and another VM clustering solution.
• More expensive, more complex.

Why a LAN/VLAN network between remote sites?

• Automatic failover of the virtual IP address with 2 nodes in the same subnet.
• Good bandwidth for resynchronization (step 3) and good latency for synchronous replication (typically a round-trip of less than 2ms).

Alternative

• Use a load balancer for the virtual IP address if the 2 nodes are in 2 subnets (supported by SafeKit, especially in the cloud).
• Use backup solutions with asynchronous replication for high latency network.

Overview of the SafeKit / Azure solution

The solution is described here: SafeKit: Microsoft Azure Load Balancing& Application High Availability Farm Cluster.

Installation of the SafeKit / Azure solution on Windows and Linux (farm.safe)

Configuration of the Microsoft Azure load balancer

The load balancer must be configured with a virtual IP address.
And the load balancer must be configured to periodically send health packets to nodes.
For that, SafeKit provides a health check which runs inside the nodes and which

• returns OK when the farm module state is UP (green)
• returns NOT FOUND in all other states

You must configure the Microsoft Azure load balancer with:

• HTTP protocol
• port 9010, the SafeKit web server port
• URL /var/modules/farm/ready.txt (if farm is the module name that you will deploy later)

For more information, see the configuration of the Microsoft Azure load balancer.

Do not configure a virtual IP address and load balancing rules at step 4 in the step by step configuration below. The virtual IP address and load balancing rules are already set in the Microsoft Azure load balancer. Setting a virtual IP and load balancing rules at step 4 is useful for on-premise configuration only.

Configuration of the Microsoft Azure network security

The network security must be configured to enable communications for the following protocols and ports:

• UDP - 4800 for the safeadmin service (between SafeKit nodes)
• UDP - 4803 for the heartbeats inside the farm module (between SafeKit nodes)
• TCP – 9010 for the load-balancer health check and for the SafeKit web console running in the http mode
• TCP – 9001 to configure the https mode for the console
• TCP – 9453 for the SafeKit web console running in https mode

Package installation on Windows

• Download and install the free version of SafeKit on 2 Windows nodes.
  Note: the free version includes all SafeKit features. At the end of the trial, you can activate permanent license keys without uninstalling the package.
• Upon completing the package installation, select Set console credentials and firewall rules now and configure a password for the admin user of the SafeKit console.
  Set the same password on all nodes.
• Exclude from antivirus scans C:/safekit/ (the default installation directory) and all replicated folders that you are going to define.
  Antiviruses may face detection challenges with SafeKit due to its close integration with the OS, virtual IP mechanisms, real-time replication and restart of critical services.

Download SafeKit (Windows) >

Package installation on Linux

• Install the free version of SafeKit on 2 Linux nodes. Note: the free trial includes all SafeKit features. At the end of the trial, you can activate permanent license keys without uninstalling the package.
• After the download of safekit_xx.bin package, execute it to extract the rpm and the safekitinstall script and then execute the safekitinstall script
• Answer yes to firewall automatic configuration
• Set the password for the web console and the default user admin. Set the same password on all nodes.

Download SafeKit (Linux) >

Note: the generic farm.safe module that you are going to configure is delivered inside the package.

Step by step configuration of the SafeKit / Azure solution

Prerequisites

• application installed on 2 nodes (or more).
• Virtual IP load balancing requires nodes on the same LAN or extended LAN (L2) — routed L3 networks not supported (except with cloud load balancers).

1. Launch the SafeKit console

• Launch the web console in a browser on one cluster node by connecting to http://localhost:9010.
• Enter admin as user name and the password defined during installation.

You can also run the console in a browser on a workstation external to the cluster.

The configuration of SafeKit is done on both nodes from a single browser.

To secure the web console, see 11. Securing the SafeKit web service in the User's Guide.

2. Configure node addresses

• Enter the node IP addresses, press the Tab key to check connectivity and fill node names. If either node1 or node2 has a red color, check connectivity of the browser to both nodes and check firewall on both nodes for troubleshooting.
• Then, click on Save and apply to save the configuration.
• Check the Success ✅ message on both nodes.
• If the configuration Failure ❌ occurs on one node, open the ▼ accordion for that node and review the messages. Note that you can use the SafeKit AI 🤖 for assistance.

If you want, you can add a new `LAN and nodes` ( first ➕) to create a second heartbeat and a dedicated replication network.

If you click on `Advanced configuration`, the `cluster.xml` file is displayed. This file is automatically populated by the console and deployed on the nodes.

3. Select a module

• In New module, click on the farm.safe module.

In the blue banner at the top, 🛜 `node1` represents the console connection node. This node relays requests to `node2` when required.

The console looks for `xxx.safe` in the `Application_Modules/generic/` directory on the connection node (`node1`) if you placed a module there during installation.

4. Configure the module

• In Module startup at boot, choose an automatic start of the module at boot without delay.
• In Macros / SERVICES, enter the service names of your application, in the startup order, separated by commas.
• In Heartbeat networks, you should have a single heartbeat network except if you have added a LAN at step 2.
• In Virtual IP addresses, enter a virtual IP address. A virtual IP address is a standard IP address in the same IP network (same subnet) as the IP addresses of both nodes.
  Application clients must be configured with the virtual IP address (or the DNS name associated with the virtual IP address).
• In Load balancing rules, set the service port to load balance (ex.: TCP 9010 in the example).
• In Load balancing rules, set the load balancing rule, Source address or Source port:
  • with the source IP address of the client, the same client will be connected to the same node in the farm on multiple TCP sessions and retrieve its context on the node.
  • with the source TCP port of the client, the same client will be connected to different nodes in the farm on multiple TCP sessions (without retrieving a context).
• In Checkers, you will be able to configure checkers if needed, such as process monitoring, custom checkers, TCP, ping, or split-brain checkers.
  For example, if a process name is displayed in Monitored processes/services, it will be monitored with a restart action in case of failure. Configuring a wrong process name will cause the module to stop right after its start.

If you click on `Advanced configuration`, the `userconfig.xml` file is displayed. This file is automatically populated by the console and deployed on the nodes with the restart scripts.

In a cloud deployment, you do not need to configure a virtual IP address and load balancing rules in SafeKit. The virtual IP and load balancing rules are managed at the cloud load balancer level.

When you apply the SafeKit configuration, the `startup type` of services is automatically set to `Manual` in Windows services. This ensures that services do not start automatically when the system boots, but are instead started only when the module itself is started (the same applies on ).

5. Edit scripts (optional)

• This step is optional and can be skipped in most cases, as the restart scripts are already pre-configured to restart services defined in the previous step.
• So, click directly on Next step.
• start_both.ps1 starts all services in the order specified in the SERVICES list, while stop_both.ps1 stops all services in the reverse order.
• Additionally, start_both.ps1 checks the startup of each service and stops the module if any service fails to start correctly.

6. Communication encryption (optional)

• Keep encryption of communication between nodes.

7. Save and apply

• Save and apply the configuration and scripts on both nodes.

8. Verify successful configuration

• Check the Success ✅ message on both nodes and click on Monitor modules.
• If the configuration Failure ❌ occurs on one node, open the ▼ accordion for that node and review the messages. Note that you can use the SafeKit AI 🤖 for assistance.

9. Start the farm cluster on node 1 and node 2

• ⋯ Start the farm cluster as shown in the image.

10. Wait for the transition to UP (green) / UP (green)

Node 1 and node 2 should reach the UP (green) state, which means that the start_both script has been executed on node 1 and node 2.

If UP (green) is not reached or if the application is not started, analyze why with the module log 🖼️ of node 1 or node 2.

• Click the 🔍 log icon of node1 or node2 to open the module log and look for error messages such as a checker detecting an error and stopping the module.
• Click on start_both in the log: output messages of the script are displayed on the right and errors can be detected such as a service incorrectly started.
• Use the SafeKit AI 🤖 for assistance with log messages.

Note that you have a 🕒 **timeline 🖼️** that can be helpful to understand what happens in the cluster.

11. Testing

SafeKit brings a built-in test in the product:

• * Configure a rule for TCP port 9010 with a load balancing on source TCP port.
  

  • Connect an external workstation outside the farm nodes.
  • Start a browser on http://virtual-ip:9010/safekit/mosaic.html.

You should see a mosaic of colors depending on nodes answering to HTTP requests.

• Stop one UP (green) node by scrolling down its contextual menu and clicking Stop.
• Check that there is no more TCP connections on the stopped node and on the virtual IP address.

Find more details, along with videos, in the SafeKit Online Training.

12. Support

• For getting support, take 2 SafeKit Snapshots (2 .zip files), one for each node.

More information on the support here.

Demonstration of the SafeKit farm solution

SafeKit Video: Network Load Balancing and Virtual IP Management (5:03)

In this video, learn how to implement a virtual IP address to provide a single entry point for a 2-node cluster. SafeKit simplifies network load balancing by automatically managing the virtual IP, ensuring that client traffic is distributed across nodes and redirected instantly during a failover. Although this demonstration uses Apache on Windows, the solution works identically with other applications.

Chapters

1. Architecture: Preparing 2 nodes for a shared Virtual IP (0:13)
2. Configuration: Setting up the farm.safe module and Virtual IP address (2:20)
3. Validation: Failover testing and Virtual IP redirection on server crash (2:30)

Step-by-Step Implementation

• Read the guide on setting up a farm cluster on Windows
• Read the guide on setting up a farm cluster on Linux

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