kubefuse - a file-system for kubernetes

Bart Spaans@Work_of_Bart

OpenCredo


https://github.com/opencredo/kubefuse/

Hello!

Lead consultant at OpenCredo

Doing infrastructure, automation, CI/CD, DevOps, ...

Semi-specialised in container based infrastructures





OpenCredo

High-end consultancy in London

Delivery of highly scalable systems

Early adopters of CloudFoundry, Docker, Mesos, Kubernetes, …

And also CQRS, Big Data, micro-services architectures, CI/CD, ...





The past year

● Kubernetes!● Kubernetes!● Kubernetes!● Kubernetes!● Kubernetes!





The next year (probably)

● Kubernetes!● Kubernetes!● Kubernetes!● Kubernetes!● Kubernetes!





What is Kubernetes anyway?

● A cluster manager inspired by Google’s Borg





What is a Cluster Manager anyway?

● A resource (CPU, Memory, Disk) aware scheduler● Control loops

For example:

deploy an application and give it two cores and four Gb of RAM, and make sure there are always ten copies running





Why use one?

● Improved resource utilisation





Why use one?

● Improved resource utilisation● Fault-tolerant





Why use one?

● Improved resource utilisation● Fault tolerant● Homogenous





Why use one?

● Improved resource utilisation● Fault tolerant● Homogenous● Enables automation

API





Kubernetes

Master

Node Node Node

Master





Key features

● Pods and services abstraction● Flat network● Load balancing and service discovery● Cloud integration● Industry backing





Pods

● One abstraction above containers● We can group multiple containers together● They share the same IP and volumes● Like a pseudo virtual machine





Replication Controllers

● Replicate pods ● Control loop ● Restart stopped pods





Services

● Load balancer for pods● Service discovery for pods● Exposing pods outside the cluster





Namespaces

● Logically group our resources in namespaces● To separate different teams, environments, organisations, …

● Nice, but slightly awkward tooling





Kubectl

● We usually interact with Kubernetes using kubectl● A command line tool that consumes the REST API

For example:

kubectl get pods --namespace=dev





KubeFuse

● A file-system view of Kubernetes resources● Read/write pods, replication controllers, services, secrets, volumes, etc.





Why?

● Less typing (+ tab completion)● Context in paths● Enables standard Linux tools (ls, cat, less, vim, find, ….)● Easy backups/exports● Continuous Deployment???






Context in path

KubeFuse

cd ~/kubernetes/dev/pods

ls

cd my-pod

cat describe

Kubectl

kubectl get pods --namespace=dev

kubectl describe pod my-pod --

namespace=dev









The KubeFuse Model

A KubeFuse path can be broken down like this:

/namespace/resource_type/object_id/action

Examples:

/default/svc/nginx/json

/default/volumes/data/describe

/dev/pod/my-cheeky-app-buu43/logs





Use case - Exploration

For example:

Listing pods, rcs, services, …

ls ~/kubernetes/default/pods

Listing all objects in the default namespace:

find ~/kubernetes/default -type d -mindepth 2





Use case - Troubleshooting

For example:

Get logs from a graphite pod:

cat ~/kubernetes/default/pod/graphite-i3bb2/logs





Use case - Quick tweaks

For example:

Update the number of DNS replicas:

vim ~/kubernetes/kube-system/rc/kube-dns-v11/yaml





Use case - Backup

For example:

Export all services as YAML:

find ~/kubernetes/default/svc -name yaml | \

while read line ; do cat $line ; echo "----\n" ; done





Use case - Continuous Delivery-ish

Coming soon!

Copy from one KubeFuse mount to the next:

cp ~/kubernetes-dev/default/pods/my-pod/json \

~/kubernetes-stage/default/pods/my-pod/json





Use case - Griefing

Coming soon!

Recursively delete everything in your cluster!

rm -rf ~/kubernetes/default/





How does it work?

● KubeFuse is written in Python● Relies heavily on FUSE and kubectl ● FUSE gives us a way to implement a file system in user space● Kubectl gives us a the Kubernetes resources● KubeFuse translates between the two





How does it work?

Caching, dealing with concurrency, permissions, modification dates, ...

More implementation details on our website: https://opencredo.com/introducing-kubefuse-file-system-kubernetes/



https://opencredo.com/introducing-kubefuse-file-system-kubernetes/





Testing

Using Myna to simulate kubectl in tests with fast feedback.

Heavily inspired by SpectoLabs’ Hoverfly, which simulates HTTP

Donated to SpectoLabs

https://github.com/SpectoLabs/myna

https://github.com/SpectoLabs/hoverfly









Demo

Give me strength.






Thanks!

Questions?

Suggestions?

Feature requests?

Version 0.6 out next week!







kubefuse - a file-system for kubernetes

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