Load Balancers
Load balancers are an important component for defining scalable and high-availability web application infrastructures. They are responsible for directing incoming network traffic to backend servers using predefined policies and algorithms.
- PDF / 1,097,918 Bytes
- 19 Pages / 504 x 720 pts Page_size
- 105 Downloads / 187 Views
Load Balancers Load balancers are an important component for defining scalable and high-availability web application infrastructures. They are responsible for directing incoming network traffic to backend servers using predefined policies and algorithms. While several networking equipment manufacturers offer dedicated, hardware- based load balancers, there are also many solutions using only software to provide these services. Generally, most cloud vendors offer load balancers as a software-defined network component, including the Oracle Cloud. Every Oracle Cloud Free Tier account comes with one Always Free eligible Load Balancer. We will explore in this chapter how we can take advantage of this offering.
Our Goal In Part 3 of this book, we will build a front-end application for the fictional Always Cloud Conference (ACC) website. With the popularity of Oracle Cloud on the rise, we anticipate that this will be a high-traffic website. To ensure that we can maintain high availability and website performance, we should host these applications on multiple servers and then have a load balancer marshal incoming web traffic to an appropriate backend server.
Always Free Limitations The list of Always Free cloud services includes a single instance of a load balancer. This is a powerful feature that is provided at no cost, but it comes with some limitations. Load balancers can be provisioned in four different bandwidth limits. These limits are based on an aggregate of both ingress and egress traffic. The various options and their bandwidth are listed in Table 8-1.
© Adrian Png and Luc Demanche 2020 A. Png and L. Demanche, Getting Started with Oracle Cloud Free Tier, https://doi.org/10.1007/978-1-4842-6011-1_8
137
Chapter 8
Load Balancers
Table 8-1. Maximum total bandwidth for the available Load Balancer options Name
Maximum Total Bandwidth (Mbps)
Micro
10
Small
100
Medium
400
Large
8000
If you have not upgraded to a paid account, then you may only select Micro. That is the only option available as Always Free. While Oracle recommends that backend servers performing the same functions be placed in different Availability Domains, there are some considerations as to whether this is possible. Some data regions only have one availability domain. For redundancy, we sometimes use other regions as a fallback. However, if you are strictly using Always Free compute instances, these approaches are not possible. Always Free resources may only be created in the account’s Home Region. However, this is moot, since Always Free Compute shapes are typically bound to one Availability Domain. Last but not least, when designing public web resources, backend servers should preferably be placed on private subnets, while load balancers are attached to a different public subnet. However, this may not be feasible given the limited number of compute instances that we can create. Placing these resources in a private subnet, or removing their public IP addresses, will require direct access to the Virtual Cloud Networks (VCN). We can
Data Loading...
