Load Balancers
Load balancer is used to distribute incoming traffic between already existing virtual machines within the same pool.
The rule consists of:
- Listener — a handler that intercepts the traffic stream coming to the balancer and responses on the configured port and protocol. It redirects traffic to the required server group;
- Pool — a group of servers of one Listener. It binds to the Listener;
- Server (Members) — specific servers within one Pool.
Our rule is a simplified model of Openstack Octavia terminology. You can use the API to solve more complex problems.
Glossary
| Term | Definition |
|---|---|
| Load balancer | Load balancer distributes incoming streams between servers in accordance with the specified parameters configured in the rule |
| Load balancer type | Depending on the tasks to be solved, the balancers are divided into three types in terms of capacity and High Availability: - basic HA (2 vCPU / 1 GB RAM / HA); - basic (2 vCPU / 1 GB RAM / Non-HA); - advanced HA (4 vCPU / 2 GB RAM / HA). The Load balancer types table shows the scenarios in which we recommend using one or another type |
| Server | Existing virtual machines that are added to process traffic flow |
| Rule | Configurations for forwarding traffic from the load balancer to the server group. In the Control panel interface, the rule combines forwarding configurations, as well as availability checks, algorithm and connection configurations, and other configurations related to this traffic stream |
| Availability check | Parameters that help the load balancer determine that the server can handle traffic. Only healthy servers will receive traffic |
| Balancing algorithm | A method for distributing tasks between multiple servers to optimize resource use and reduce requests serving time |
| Connection configurations | Configurations for all connections passing through the balancer: number of requests, connection timeouts and response waiting time |
Load Balancer Types
The load balancer type determines its capacity and High Availability. Different types of load balancers can be used depending on the project and workload:
| Load balancer type | High Availability |
Redundancy | Description | Load balancer characteristics |
|---|---|---|---|---|
| Basic HA | V | Yes, Active-Standby Failover is available | Best for small to medium projects where service availability is critical | Bandwidth: max 5 Gbps Number of HTTP requests: ~ 19,5K Number of HTTPS requests: ~3K keep-alive connections |
| Basic | X | No, Single mode only | Best for test environments, as well as for projects where 24 / 7 service availability is not critical | Bandwidth: max 5 Gbps Number of HTTP requests: ~19,5K Number of HTTPS requests: ~3K keep-alive connections |
| Advanced HA | V | Yes, Active-Standby Failover is available | Best for projects with high workloads and continuous service availability | Bandwidth: max 5 Gbps Number of HTTP requests: ~34K Number of HTTPS requests: ~9K keep-alive connections |
If necessary, you can order a custom configuration of the load balancer. You need to create a ticket for this.