Is Rust a great language for building Kubernetes ecosystem

@deepu105
@oktaDev
Is Rust a great language
for building the
Kubernetes ecosystem?
Deepu K Sasidharan
@deepu105 | deepu.tech

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@deepu105
@oktaDev
Deepu K Sasidharan
JHipster co-lead, Java Champion
Creator of KDash, JDL Studio
Developer Advocate @ Okta
OSS aficionado, author, speaker, polyglot dev
@deepu105
deepu.tech
deepu105

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@deepu105
@oktaDev
What is KDash?

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@deepu105
@oktaDev
KDash
● A simple terminal dashboard for Kubernetes
● Provides resource views, Node metrics, logs and common view features
● Resources utilizations for nodes, pods and namespaces based on metrics
server.
● Context switching
● Easy full keyboard navigation and themes
https://github.com/kdash-rs/kdash

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@deepu105
@oktaDev
KDash - Context overview

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@deepu105
@oktaDev
KDash - Utilization metrics

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@deepu105
@oktaDev
Why did I build another
Kubernetes dashboard?

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@deepu105
@oktaDev
Why another dashboard
Kdash is obviously inspired by k9s, so why build another dashboard?
● User experience: I wanted the stuff that is most used easily available and a
workflow suitable for daily use
● Better navigation: I wanted a better overview and keyboard shortcuts for
everything
● Better metrics: I wanted to see better resource metrics for the cluster
● PoC for Rust tooling: I wanted to build something useful in Rust for the k8s
space
● Speed: While Go based tooling can be almost as fast, I wanted to build
something faster and efficient with Rust. Why not?
○ KDash uses way less memory/cpu than k9s and even Kubectl watch

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@deepu105
@oktaDev
Why Rust? Why not GoLang?

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@deepu105
@oktaDev
Rust = High level general purpose language
● Multi-paradigm, ideal for functional, imperative and even OOP
● Modern tooling
● Ideal for systems programming, embedded, web servers and more
● Memory safe
● Concurrent
● No garbage collection
● Performance focused
● Most loved language in Stack Overflow survey for 6 years in a row

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@oktaDev
Safe programming
Programming Safety = Memory safety + Type safety + Thread safety

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● About 70% of all CVEs at Microsoft are memory safety issues
● Two-thirds of Linux kernel vulnerabilities come from memory
safety issues
● An Apple study found that 60-70% of vulnerabilities in iOS and
macOS are memory safety vulnerabilities
● Google estimated that 90% of Android vulnerabilities are
memory safety issues
● 70% of all Chrome security bugs are memory safety issues
● An analysis of 0-days that were discovered being exploited in
the wild found that more than 80% of the exploited
vulnerabilities were memory safety issues
● Some of the most popular security issues of all time are
○ Slammer worm, WannaCry, Trident exploit, HeartBleed, Stagefright, Ghost
CVE galore from memory safety issues

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@deepu105
@oktaDev
Security issues from thread safety
● Information loss caused by a thread overwriting information from another
○ Pointer corruption that allows privilege escalation or remote execution
● Integrity loss due to information from multiple threads being interlaced
○ The best-known attack of this type is called a TOCTOU (time of check to
time of use) attack caused by race conditions

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@deepu105
@oktaDev
Security issues from type safety
● Low level exploits are possible in languages that are not type safe.
● Type safety is important for memory safety as type safety issues can lead to
"For comparison, last week we caught a significant race condition in another Kubernetes-related
project we maintain called Helm (written in Go) that has been there for a year or more, and which
passed the race checker for Go. That error would never have escaped the Rust compiler, preventing
the bug from ever existing in the first place." – Microsoft team

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@deepu105
@oktaDev
Zero cost abstractions
“What you don’t use, you don’t pay for. And further: What you do use, you couldn’t
hand code any better.”
– Bjarne Stroustrup
● Your programming style or paradigm does not affect performance
● Number of abstractions does not affect performance as the compiler always
translates your code to the best possible machine code
● You could not get more performance from hand written optimizations
● In-built abstractions are often more performant than hand written code
● Compiler produces identical assembly code for almost all variations

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@oktaDev
Zero cost abstractions

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@oktaDev
Tooling and community
● Hands down, one of the best compilers out there and great backward compatibility
● One of the best tooling you can ﬁnd in terms of features and developer experience. Cargo is one
stop shop for Rust tooling, build, compilation, formatting, linting, and so on
● One of the best documentation, which is shipped with the tooling
● A very diverse and vibrant community
○ Community formed from other languages hence bringing in best of many
○ Very welcoming and helpful
○ Rapidly maturing ecosystem with growing number of libraries and use cases
○ Has a forum which is used more than stack overﬂow for Rust
● Big names like Google, Apple, Microsoft, Amazon and Facebook are already behind rust and
investing it.
● It’s on path to become the second supported language in Linux development.
● Use case has already extended to embedded, web assembly, kubernetes, web development, game
development and even client side
● It’s only a matter of time until you can do any use case in Rust

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@deepu105
@oktaDev
Rust can be the ideal general
purpose language

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High level vs Low level language
High level language
● Human oriented
● Easier to read
● Portable
● Need to be compiled to
machine code
● Not as efficient as a low
level language
● Provides features like
memory management,
abstractions and so on
Low level language
● Machine oriented
● Harder to read
● Hardware specific
● Can be understood by machines
● Fast and efficient
● No fancy features

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@deepu105
@oktaDev
High level language compromise
● Safety
● Speed
● Abstractions
Pick two

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@deepu105
@oktaDev
High level language compromise
● Safety
● Speed
● Abstractions
With Rust we can get all three. Hence Rust is a high level language with
performance and memory efficiency closest to a low level language. The only
tradeoff you will make with Rust is the learning curve.

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@deepu105
@oktaDev
Performance, Memory and power
From the research paper “Energy Efficiency across Programming Languages”

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@oktaDev
“Rust, not Firefox, is Mozilla’s greatest
industry contribution”
– TechRepublic

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@oktaDev
Use cases and Ecosystem

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WebAssembly
● WebAssembly System Interface (WASI) makes it possible to run Wasm workloads in
Kubernetes
○ Still quite new and has a lot of rough edges
○ Could be the future of containerless Kubernetes.
● Rust has one of the best tooling and ecosystem for WASM making it an ideal language to
build WASI workloads for Kubernetes as well.
● Wasmtime (a JIT-style standalone runtime) makes it possible to run Wasm outside of a
browser and it is written in Rust.
● WasmEdge is another runtime focused on microservices built using C++ and Rust.
● WasmCloud is another runtime focusing on distributed actors and is written in Rust.
● Krustlet is a Kubelet written in Rust and can run WASM OCI workloads in Kubernetes.
https://developer.okta.com/blog/2022/01/28/webassembly-on-kubernetes-with-rust

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In cluster tools
● Proxies/Sidecars/ServiceMesh
○ Speed, safety and efficiency of Rust makes it the best choice for proxies and
sidecars
○ Linkerd proxy is written in Rust
● K8s Operators
○ Rust’s asynchronous programming model is a perfect match for building high
performance/throughput/parallel operators
○ Light on resource usage and footprint and less code to write
● Log aggregation/Monitoring/eBPF
○ Ideal for low footprint observability/tracing
○ Redbpf: A Rust eBPF toolchain already exists

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User space tools
● KDash: uses very minimal resources compared even to kubectl
● Kubie: K8s context switching and prompt modification for shell
● kubectl-view-allocations: kubectl plugin to list allocations
● Click: Command Line Interactive Controller for Kubernetes

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@deepu105
@oktaDev
Notable Libraries
● kube-rs: Kubernetes client for Rust
● K8s-openapi: Rust bindings for Kubernetes API
● kubert: Rust Kubernetes runtime helpers
● Roperator: Write kubernetes operator in Rust with minimal code
● Rusoto: Rust SDK for AWS
● aws-sdk-rust: Rust SDK for AWS
● Prometheus-parser: parse and validate Prometheus query expressions

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@oktaDev
KDash architecture

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Major Libraries used
● tui-rs: Library to build rich terminal user interfaces and dashboards
● Crossterm: Terminal manipulation library
● Tokio: An event-driven, non-blocking async I/O platform
● kube-rs (k8s-openapi, Openssl): Kubernetes client for Rust
● kubectl-view-allocations: Library to fetch resource allocations for k8s
● clap: Command line argument parser
● rust-clipboard: cross-platform library for OS-level clipboard management
● duct.rs: Library for running child processes
● Serde: Serialization and deserialization library

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Data architecture
● Event driven
○ Async I/O using dedicated channels
● Multi threaded
○ Single data-store using ARC + Mutex
○ Separate threads for UI, streams, network and CMD
● Non-blocking UI
○ Only bottleneck is network I/O with kube-api-server

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@oktaDev
Challenges

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@oktaDev
Challenges
● Log streaming was blocking due to how the kube-rs lib works
○ Solution: Seperate thread for log streaming with tokio-streams
○ Some quirks exists and needs to be investigated and fixed
● UI was blocking and not very smooth
○ Solution: Seperate thread for network calls and event driven I/O
● Kube-rs version updates are coupled to another library used
○ No proper solution yet

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@deepu105
@oktaDev
Thank You
Deepu K Sasidharan
@deepu105 | deepu.tech
https://deepu.tech/tags#rust

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Is Rust a great language for building Kubernetes ecosystem

Is Rust a great language for building Kubernetes ecosystem

Deepu K Sasidharan

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