What Is an AWS Gateway Load Balancer and What Are Its Benefits?
The AWS (Amazon Web Services) Gateway Load Balancer provides load balancing benefits to third-party virtual appliances. At the same time, the service intends to make these third-party virtual appliances highly available and scalable with minimal administrative overhead. This article discusses what load balancing is, the more popular load balancing algorithms, the use cases for AWS Load Balancing, issues in load balancing, and how Parallels® RAS can enhance load balancing.
Definition of a Load Balancer
High-traffic websites, web applications, and the databases that run behind them get millions of incoming requests and queries during peak hours. When large files such as images, audio, and video are passed between users and servers at such times, the risk of slowing down servers and their response times becomes real. To prevent this from happening, more servers are added to accommodate incoming requests.
Another option to better serve incoming traffic is to add load balancing capabilities to your network. Load balancers can come in the form of hardware or software and act as intermediaries between users and servers, keeping track of server loads so that they will know which server can handle incoming traffic better.
When an incoming request comes in, the load balancer knows which server to send it to. When a server is not available, the load balancer knows and bypasses that server accordingly. When the server goes up again, the load balancer will route requests to it again. It will also know when a new server is added to your network, allowing it to route requests to that server when the time comes.
Popular Load Balancing Algorithms
Load balancers make decisions on where to send incoming requests based on algorithms for optimizing network traffic.
While the algorithm you select for your network depends on your requirements, your IT team must select which algorithm to use when it sets up your load balancers. The more popular load balancer algorithms include:
- Round robin: Under this setup, the load balancer makes decisions based on the sequence of servers in your network. Thus, Server 1 is the first to handle a request, then Server 2 and onward. As it does not account for server load, this algorithm can lead to some servers getting overloaded with requests. A variation of this is the weighted round-robin, which assigns weights to servers based on their capabilities.
- Least connection: With this setup, incoming requests are sent to servers with the least number of active connections. Thus, it helps avoid the potential problem of server overload.
- Least bandwidth: This setup measures the amount of traffic transmitted to and from servers, with the server having the least bandwidth consumption eventually getting the request. This is like the least packets method, which bases the load balancer’s forwarding decision on the number of packets the server transmits over the network.
- Least response time: Under this setup, the load balancer sends monitoring requests to servers to determine how fast they can serve a request before forwarding the actual request to the server that can handle the request faster.
- Hashing: With this setup, the load balancer relies on hash data from incoming network packets, including the Internet Protocol (IP) addresses of the source and destination. This can be complicated to set up, making it more difficult than the other algorithms discussed in this section.
- Custom load: This setup involves querying server loads based on data provided by SNMP (Simple Network Management Protocol), including memory usage, CPU usage, and response time, with the load balancer relying on the data to make its routing decision.
Use Cases for AWS Gateway Load Balancer
Just like any other load balancer, the AWS Gateway Load Balancer serves to organize your network traffic so that your users can be served better and faster. Secondary to this is that it can allow your virtual appliances to scale on demand. Thus, if your organization currently uses or is planning to use virtual appliances, the service is intended primarily for you. Some examples of virtual appliances include those that strengthen your network security, including firewalls and intrusion detection systems.
The AWS Gateway Load Balancer takes care of routing traffic to the appropriate virtual appliance in your network, instead of traffic going directly to virtual appliances. With the Gateway Load Balancer, traffic is routed to healthy virtual appliances and rerouted away from failing ones. Thus, it can help reduce administrative costs since you can centralize traffic through the gateway. It can also ensure that your policies are enforced consistently across your appliances.
Through the AWS Marketplace, your organization also has access to third-party virtual appliances and solutions that can be added to your network with minimum fuss. These come at a price, though, so you still must allot a budget for these expenses.
Since any third-party virtual appliance or solution can be connected as-is to the AWS Gateway Load Balancer without the need to alter any other endpoint, they are ideal for network analytics, allowing you to catch potential network issues early on and making your network more resilient. Moreover, the AWS Gateway Load Balancer also works with network orchestration tools. Among these tools is AWS CloudFormation, which eases the deployment and management of AWS resources in your IT infrastructure.
Issues with Load Balancers
While load balancers have their benefits, they are not exempt from issues that can complicate your network and the work of your IT teams.
Load balancers can make your network more complex than it already is. If your load balancer goes down, it can take your whole network down as well. A failover mechanism for your load balancing infrastructure must be implemented to prevent this from happening.
One way to achieve this is through redundant routers that can switch traffic from one load balancer to another in case of failure. With such a mechanism in place, when the primary load balancer fails, a backup load balancer takes over its functions until the primary load balancer goes back online.
The failover requirement above means that load balancers can lead to higher operational costs for your network.
Load balancer misconfiguration can also bring about network problems. For example, it can happen that load balancers may detect failure incorrectly in healthy servers and reroute traffic to other servers needlessly. This can be due to several factors, including too frequent health checks and too short time-out periods for when a response is expected from your servers during health checks. Adjustments to the frequency of health checks and making timeout periods longer can help resolve this issue.
Highly Efficient and Secure Load Balancing with Parallels RAS
Parallels RAS is a complete remote working solution that offers comprehensive load balancing capabilities, including the ability to handle Remote Desktop Session Host (RDSH) servers. It can also load balance internal components such as its own Parallels RAS Gateway.
Parallels RAS is easy to set up—you are not required to go through any complicated procedures to get it up and running. You also do not need to acquire expensive add-ons to make it work. Instead, Parallels RAS offers all these capabilities using a single, full-featured licensing model.
You can choose from either resource-based or round-robin load balancing when setting up Parallels RAS. With resource-based load balancing, sessions between servers are distributed based on the current server load. On the other hand, round-robin load balancing redirects traffic to servers based on the order in which it was received. Both these methods are easier to set up than the more complicated load balancing algorithms.
Parallels RAS supports virtual private cloud and wide area network (WAN) load balancing scenarios. Parallels RAS can also direct traffic to healthy gateways with its High Availability Load Balancing (HALB) capability. This helps minimize single points of failure in your network. As it also supports AWS Elastic Load Balancer (ELB), you can deploy AWS ELB for load balancing your Parallels RAS environment with ease.
