SRE interview questions and job descriptions (2023)

Sample Site Reliability Engineer job description

Do you enjoy working with a highly motivated and talented team to deliver mission-critical software? [Company Name] is expanding our Site Reliability Engineering team to help deploy, manage, troubleshoot, and improve our complex cloud-based services for a variety of customers.

As a Site Reliability Engineer, you will design and implement web applications and REST API services using a microservices-based infrastructure to replace our current monolith implementation. The new technology stack includes [Amazon Web Services (AWS)/Google Cloud/etc.], [Docker/Kubernetes/other], [relational database], [NoSQL/NewSQL database] and [monitoring tool]. Your focus is on maximizing system availability. All team members take part in an on-call service.

They develop innovative automated solutions and tools to debug and resolve problems in production and prevent them from reoccurring. In addition, you proactively look for system weaknesses and find ways to fix them before they cause production problems by monitoring, observing trends and using dataChaos-Engineering.

responsibilities

• Keep your assigned site or service running or quickly get it back up and running if an error occurs
• Working closely with internal partners and teams to ensure we deliver software that meets security, SLA and performance requirements
• Writing, updating and using documentation including runbooks/playbooks
• Automate work including infrastructure requirements, testing, failover solutions, error mitigation and more
• Debug complex problems across an entire stack and build solid solutions
• Development of CI/CD processes to improve cadence
• Use Chaos Engineering to test what you build in real-world conditions

Key Qualifications and Attributes

Necessary

• 7 years of experience in software engineering, software development or system operation
• Excellent communication skills, both oral and written
• Familiar with a Unix/Linux shell, can write shell scripts and understands Linux internals
• Experience debugging complex problems
• Experience in designing, building and operating large production systems
• Knows Python, Java, Go, Rust or similar
• Understands networks and messaging, especially between services
• Has hands-on experience with source control (Git, GitHub) and feature branching strategies
• Has experience with a variety of open source databases (MySQL, Postgres, Redis, Cassandra, etc.)

Preferred

• experiences withDevOps-Engineering oder SRE
• Experience with containers, e.g. B. with Docker or Kubernetes
• Experience with monitoring and observability such as Datadog, Sensu, New Relic and Nagios
• Experience the automation of infrastructure, tests and deployments with tools like Ansible, Chef or Terraform and be able to explain the infrastructure-as-code paradigm
• Experience with configuration management, e.g. B. with Puppet
• Understand the idea behind itChaos-Engineering, even if they haven't implemented it themselves

A single candidate is not expected to have expertise in all of these areas - we look for candidates who are particularly strong in some areas and have a certain interest and ability in others.

Our mission at [company name] is [insert company mission]. Our products help software companies [do something great] - and empower companies and individuals to [save time and money]. Our customers include [name], [name], [name] and [name]. [Company] is a unique workplace and offerscompetitive compensation packagesThis includes medical, dental and ophthalmic services with flexible PTO and 401,000 with company-specific contributions [up to X%].

[Company] has an [Industry] startup culture that emphasizes transparency, collaboration and career growth, with the ability to work in small, flexible teams. People have the power to create change at scale and the ability to really disrupt and shape [the industry].

[Company] is an Equal Opportunity Employer. Qualified applicants will be considered for employment without regard to race, color, religion, sex, sexual orientation, gender perception or identity, national origin, age, marital status, protected veteran status, or disability status.

Learn more at [Company URL].

Sample Site Reliability Engineer Interview Questions

Our sample questions do not form a complete set, and we do not recommend anyone use them without first understanding the needs of the hiring company and team. Modify the questions to find someone a great fit for the role the team needs to fill. Many would also make good DevOps interview questions. The important thing is to see how the questions fit well into your interview process. Most of our sample questions focus on the technical interview.

The aim of these questions is to assess a candidate's knowledge, experience and ability to interact with the interviewer while responding with professionalism and clarity. We would only expect the top candidates for leadership positions to answer all of these questions, but how a candidate is transparent about not knowing the answer and talks about how they would approach solutions is one of the most valuable indicators, on What to look out for at a job interview.

What is an SLO?

A Service Level Objective (SLO) defines the target availability (uptime) we want for a system or service. We define reliability as meeting our SLOs.

Follow up: What is an SLA? An SLI?

A Service Level Agreement (SLA) is the promise of availability that we make to a customer. These are often defined by law with penalties for missing target availability. Because of this, SLAs are generally set using numbers that are easier to meet than SLOs.

A Service Level Indicator (SLI) is something you can measure precisely to help you reflect, define, and determine whether you are meeting SLOs and SLAs. They are generally given as the ratio of the number of good events divided by the total number of events. A simple example would be the number of successful HTTP requests / total HTTP requests. SLIs are often given as a percentage, where 0% means everything is broken and 100% means everything is working perfectly.

What is a linked list?

It is a data structure where each data item is a separate item in a list. Elements are connected (linked) with pointers. The list begins with a header that points to the first node in the list. The header is followed by nodes containing a data element and a reference to the next data element. The last node, the end, contains the data item and a reference to null indicating the end of the list.

Name some other data structures.

Queue, stack, heap, hash table, binary tree, etc.

Depending on your needs, this could continue with a question about data algorithms.

What is DNA?

This is a BIG question and it will be interesting to see how the candidate answers. Ultimately, one is not necessarily looking for comprehensive knowledge, but whether one can name the main points of interest and do so with clear definitions.

The Domain Name System (DNS) is a decentralized naming system for resources connected to the Internet or a private network. These resources are assigned Internet Protocol (IP) addresses, which are defined strings of unique identification numbers that follow a precise format. However, humans can hardly remember IP addresses, so DNS allows assigning a human-readable name like google.com to be used in place of the IP address.

You can also read about IPv4 versus IPv6, DNS records and the fields involved and how to create them, name servers and decentralization and the existence of a set of canonical root name servers, queries, caching, primary versus secondary DNS settings, reverse DNS lookups, DNS talk zones and security concerns. All of this is important, but you really look to see if the candidate understands the big picture and how they are conveying it to you.

Name three types of databases and an example of each. Name a few that you have used.

You must name relational databases as one of the types, like MySQL, Postgres, Oracle and so on.

Then we look for other databases that you know or are familiar with. The candidate should be able to describe the difference between each type they name. Here are some examples:

Key/value stores: BerkeleyDB, Cassandra, etcd, Memcached and MemcacheDB, Redis, Riak

Document storage: CouchDB, MongoDB

Wide Column Stores: BigTable, HBase

Graphics storage: FlockDB, Neo4j, OrientDB

What is an inod?

An inode is a data structure in Unix/Linux that contains metadata about a file. Some of the elements contained in an inode are:

• Modus
• Owner (UID, GID)
• Size
• atime, ctime, mtime
• acl
• a blocking list where the data is located

The filename exists in the inode structure of the parent directory.

What is the difference between RAID 0 and RAID 5 and when would you choose one over the other?

RAID 0 uses striping, which splits the data across two or more disks. RAID 5 is striping with parity, which provides some error detection. RAID 0 strictly emphasizes performance, while RAID 5 introduces fault tolerance at the expense of slightly lower performance.

When a file system is full and you see a large file taking up a lot of space, how do you free up space in the file system?

There are several options. We want at least one or something just as good. Perhaps ask a question about when/why their answer might be appropriate and when another option would be better.

• If no process has the file handle open, you can delete the file.
• If a process has the file handle open, it's better if you can't delete the file but can do socp /dev/nullon the file, reducing its size to 0.
• A file system has a reserve, you can reduce the size of this reserve to make more space with tunefs.

What are the most common signals used with the Linux kill command? What is everyone doing? What is the default? When is each appropriate?

• kill -15sends a TERM signal trying to gracefully stop a process. It's the default.
• kill -1sends a HUP signal that reloads a process.
• kill -9sends a KILL signal terminating a process.

A good way to follow this is with a discussion of important system calls.

Provide a definition of virtualization, containers, and Kubernetes and explain how the three are related and different from each other.

Bonus points if they start talking about a bare metal server.

Virtualization installs a control plane over a set of bare-metal servers to create a resource pool from the combination of those servers' physical resources. You can then create "virtual machines" that have a different combination of memory, storage, and processor resources as needed, with each machine having its own operating system. Virtual machines can be created and destroyed quickly and easily.

Containers are similar except they don't contain the base tier operating system. Instead, the control layer provides access to the operating system while keeping the containers and their processes isolated from one another. Containers encapsulate software, such as a microservice, along with any software dependencies required to run that software. This provides insulation and flexibility.

Kubernetes adds an orchestration layer to containers, making them easier to manage, especially large systems.

Was ist Cloud-Computing?

Common answers are "using someone else's computer" or running services on devices in someone else's data center. Then ask a question as to why companies use one of the different cloud platforms (save money, outsource maintenance, etc.).

Please describe an issue you had to fix, how you found it, and how you fixed it.

They look at their thought process, their organization, and how methodical they are in finding sources of problems. They are also looking for how creative they can be in solving them.

What are some common architectural bottlenecks and some potential ways to mitigate problems?

Every architecture is different, so look for them to mention network issues, resource allocation, unusual service interactions, and so on.

What steps would you take to secure a container image?

Do the candidate's steps match those of your company? Close? Is the candidate open to suggestions or pretending to have the definitive answer (like a know-it-all)?

What's your favorite way to interact with team members? Describe your ideal team. Describe the best team you have worked with. Describe a time when you had an issue with a colleague and what you did to make the relationship work.

You want to know how the candidate thinks about interacting with colleagues to gauge how those thoughts align with your company's current culture and the culture you want in the future.