Are you preparing for an interview and need to brush up on F5 Load Balancer concepts? This blog post will help you review and practice the most commonly asked F5 Load Balancer interview questions. With a deep understanding of the F5 Load Balancer technology, you’ll be well-prepared to ace your interview.
We’ve compiled a list of the 22 most basic F5 Load Balancer interview questions designed to assess your expertise in the field. Each of these questions is designed to test your knowledge and understanding of the Load Balancing concepts and concepts related to the F5 Load Balancer. We’ll explain and provide answers for each of these questions, so that you can gain a deeper understanding of the technology and be prepared to answer questions during your interview.
These questions cover a wide range of topics, from basic concepts and components of the F5 Load Balancer to more advanced ideas and solutions. We’ll explore each of these questions in detail, so that you
- Q3: – What is Health Check in refer to load balancer ? …
- Q4: – When load balancing to a real server, which server will be accessed first? …
- Q6: -What is Global Server Load Balancing (GSLB)? …
- Q7: – Does Clustering need to be turned on in order to use GSLB?
F5 Interview Questions Part 01
F5 Load Balancer Interview Questions to prepare in 2021
Welcome to F5 Load balancer interview questions. One of the top MNCs offering (ADN)application delivery networking and application services is “F5 networks.” The primary concerns of this company are security, performance, availability, and delivery. F5 is accessible in environments that use multiple clouds, including Microsoft Azure, AWS, open stack, and Google Cloud.
We have compiled a list of F5 load balancer interview questions that are appropriate for both new and seasoned candidates in order to streamline your interview process. The confidence you will gain from practicing these interview questions will help you succeed in the interview. All the very best!!.
Frequently Asked F5 Load Balancer Interview Questions and Answers
Well, there are two types of load balancers: software-based and hardware-based. The software-based load balancer (VIPRION of BIG-IP) is loaded into the hardware (machines) by hardware manufacturers like F5 Networks and Citrix.
A series of load-balancing algorithms used by SLB (Server Load Balancing) deliver content and network services. Its automatic prioritization of the responses that must be sent in response to a specific client request on the network is one of its outstanding features.
SLB guarantees application reliability, high availability, scalability, and delivery.
SLB utilizes two different types of load balancing, namely:
Application-level load balancing: WSLB (Windows Server Load Balancing) and other balancing techniques use traffic load as a criterion.
DNS-based approach for load balancing at the transport level that does not require an application payload
The three benefits of using SLB are:
Any appliance that performs cookie load balancing needs the information listed below to be configured:
To assess the Server status, use the health check feature. For instance, SLB will prevent sending client requests to a failed server in the network if the Health server identifies that server as such.
iControl gives fine-grained control over the management and configuration of F5’s application delivery platform because it is a web service-enabled API.
SBL and global server load balancing are very similar, but global server load balancing allows us to load balance VIPs from different geographic locations as a single entity. GSBL also provides geographical site scalability and fault tolerance.
The simplest way to enable GSLB is with the help of CDN(Content Delivery Network). Global CDN will obtain information from the origin servers of their customers and cache the data on the geographical servers and deliver reliable internet content to users across the world.
Persistent cookies are usually stored in the user’s device. These cookies enable us to remember information, preferences, and settings as well as our user credentials. In essence, these cookies are intended to provide users with a convenient website experience.
Yes, turning on clustering is very important to utilize GSLB. Every proxy inside the cluster should have a similar configuration. Therefore, if an appliance becomes a site master, it can act as a DNS.
Overflow is the term used when there are more requests than the site can handle. When 80% of the local site is loaded, one of the methods in the array GSBL called overflow sends the requests to another site, which fixes the issue.
Clients will be directed to sites with the fewest active connections by the “least connections” method.
One of the simplest ways to distribute client requests among a cluster of servers is through round-robin. This algorithm instructs the load balancer to repeat the process until there are no more requests as each request is routed to one of the servers in the group.
Different load balancing techniques are:
A pool is a collection of hardware, such as web servers, used to gather and handle traffic. The target IP address specified in the client request is not where BIG-IP sends client traffic. The request is instead sent to the nodes that are a part of that pool.
Your load balancer’s nodes will assist you in transferring client requests to the specified destination. Simply put, the node serves as a medium for transporting client requests to your targets.
We can serve content to clients directly from the memory of your F5 appliance thanks to RAM cache. Because the RAM cache lowers server load and response latency, both the server and client can benefit.
Following is the non-cacheable content in RAM cache:
The shortcut for refreshing or clearing the cache is ctrl+F5.
Pipelining is a method where different requests are sent over a single TCP connection without anticipating responses. In the same order that the requests were received, the server will send back the responses.
The iRule was created because the extended capabilities needed are not all provided by CLI and GUI. We create this type of script to make use of the capabilities that the GUI and CLI do not offer. This iRule will enable us to communicate with the traffic passing by that device directly.
There are three essential elements in iRule they are:
We must define the following variables within the cluster configuration:
SNAT (source network address translation) converts an HTTP request’s IP address from a source client to a translation address specified on the BIG-IP device.
DNAT is abbreviated as Destination network address translation. This enables us to reroute the packets to a particular IP address.
The levels that can be reached from the home page are referred to as the recursion depth. This is how we tell the cache how many levels of the website to preload.
In F5 load balancing, there are two different kinds of cookie policies. They are:
While unchecked exceptions can be checked at program compile time, checked exceptions can be checked at program run time. Both the checked and unchecked exceptions can be generated manually.
In order to define the behavior of the cache replacement based on the context, the hardware load balance cache makes use of several algorithms. When we run out of space, the hardware load balancer frequently uses Least Recently User (LRU) to delete the older content.
To succeed in the interview, you must possess in-depth knowledge of and expertise in server load balancing. Interviewers frequently test candidates with the aforementioned F5 interview questions.
Employers will evaluate your depth of knowledge based on all the questions. Therefore, we advise you to be ready with responses to the F5 Interview Questions. Finally, giving accurate answers to these F5 interview questions will help you land the job of your dreams at the company of your dreams.
F5 Networks is a global multinational company which specializes in application services and application delivery networking (ADN). They focus on availability, performance, security and delivery. F5 headquarters in Seattle, Washington. F5 Technologies is present in the data center and cloud. It is available in private, public and multi-cloud environments on platforms like AWS, Microsoft Azure, Google Cloud and Open Stack.
Investing in F5 Training and Certification Courses may help you succeed in interviews.
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Top F5 Load Balancer Interview Questions and Answers
In response to network requests, Server Load Balancing (SLB) uses a variety of strategies and prioritization to enhance network speed and content delivery. SLB distributes users among a group of servers and ensures that users are not forwarded to malfunctioning servers.
SLB utilizes two distinct forms of load balancing:
To begin, load balancers are classified as software-based and hardware-based. Hardware vendors like F5 Networks and Citrix incorporate the software-based load balancer into their goods.
You’ll require the name and value of the cookie, the VIP you’re binding to, and the groupings you’re balancing.
You can configure settings for performing diagnostics on the functionality of web servers connected with each appliance using the load balancer’s Health Check function. You can use health checking to determine whether a server or resource is working properly or has stopped working.
The three advantages of utilizing SLB are as follows:
Granular control over F5’s application administration and customization platform is offered by the web service-enabled Application Programming Interface known as iControl.
Similar to SBL, Global Server Load Balancing allows us to load balance VIPs from various geographic locations as a single entity. Additionally, GSBL enables geographic site expansion and low latency.
Utilizing a CDN (Content Delivery Network) is the simplest way to enable GSLB. Global CDN will gather information from their clients’ origin servers, cache it on widely spaced-out servers, and provide trustworthy internet content to users everywhere.
Typically, persistent cookies are retained on the user’s device. These cookies allow us to remember user information, preferences, and settings as well as their login credentials. Basically, the purpose of these cookies is to improve the user’s online experience.
According to the Persistent Cookie strategy, a cookie is assigned to a group based on its name. Based on the name and value of the cookie issued to that unit, a QoS Cookie policy chooses the server group to which a cookie is assigned.
This is determined by the load balancing strategy you choose. Following are a few examples:
As the name suggests, Reverse Proxy Cache is a type of caching that is located close to the source server. The proxy will respond from the cache rather than the origin server when a user requests a cached item.
Yes, in order to use GSLB, clustering must be enabled. Every proxy in the network ought to have a similar configuration. Therefore, if a device becomes a zone master, it can perform DNS functions.
Overflow occurs when there are more queries than the server can handle. When the local site reaches 80% of its capacity, one of the array GSBL’s techniques called overflow directs queries to another server.
Clients are directed to websites with the fewest recent links using the “least connections” approach.
One of the simplest methods for distributing client requests among a group of servers is round-robin. This protocol instructs the load balancer to carry out the process as each query is sent to one of the group’s servers, continuing until no more queries are received.
Various load balancing strategies include the following:
A pool is a collection of equipment, such as web servers, that work together to collect and handle the traffic. BIG-IP does not route client information to the specified destination IP address in the user requests. Rather than that, it transmits the request to the subscribers of that group.
You will receive assistance from the load balancer’s nodes in directing client inquiries to the designated location. Simply put, the node acts as a conduit to allow the client’s request to reach its target.
FAQ
What is F5 load balancer interview questions and answers?
- Question 1: What do you mean by load balancing pool? .
- What is the IP address for the default MGMT port on the F5 BIGIP LTM?
- Question 3: What is iRule in F5 BIGIP LTM? …
- Question 4 – What is iControl? …
- Question 5 – What is OneConnect? …
- Question 6: What is a profile in BIGIP LTM?
How does an F5 load balancer work?
The device known as a load balancer serves as a reverse proxy and distributes network or application traffic among several servers. Applications’ capacity (number of concurrent users) and dependability are increased with the aid of load balancers.
Is F5 load balancer Layer 7?
It offers Layer 4–7 load balancing and Layer 7 traffic management, making it possible to optimize and offload other network resources, such as VAS servers.
Is F5 a firewall or load balancer?
You can use F5 to examine and encrypt all traffic moving through your network. The solution has load-balancing, application firewall, and proxy features.
