Gluster and Kubernetes
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GlusterFS can be used with Kubernetes in several ways: 1) As a volume driver to provide persistent storage and shared access to data across containers using existing GlusterFS volumes. 2) Through local volumes which use hostPath provisioning to leverage GlusterFS mounts but are not suitable for production. 3) With Heketi which provides dynamic provisioning of GlusterFS volumes through a REST API and integration with Kubernetes. 4) Potentially through Rook which aims to integrate storage services like Ceph and GlusterFS to provide turnkey storage and currently supports Ceph.
Gluster and Kubernetes
- 1. GlusterFS & Kubernetes The State of GlusterFS Support in Kubernetes
- 2. Joe Julian ● Long time community member. ● Senior Staff Engineer with Samsung SDS/CNCT. ● Certified Kubernetes Administrator (my first cert ever, hope it’s worth the paper it’s printed on)(I haven’t printed it). ● Insufferable know-it-all with an opinion about everything.
- 3. What is Kubernetes Kubernetes is ancient Greek for "Helmsman". Root of the word "Governor", "Cybernetics". Kubernetes is a "Container Orchestrator" or "Cluster Manager". ● Places containers on nodes ● Recovers automatically from failure ● Basic monitoring, logging, health checking ● Enables containers to find each other.
- 4. How can gluster be used with Kubernetes ● Persistent state Containers can be restarted at any time due to failed liveness check or deployment.
- 5. How can gluster be used with Kubernetes ● Persistent state ● Shared Storage Multiple containers may need to operate on the same data set.
- 6. How can gluster be used with Kubernetes ● Persistent state ● Shared Storage ● Cats
- 7. How can gluster be used with Kubernetes ● Persistent state ● Shared Storage ● Cats
- 9. GlusterFS Volume Driver volumes: - name: glusterfsvol glusterfs: endpoints: glusterfs-cluster path: kube_vol readOnly: true kind: Endpoints metadata: name: glusterfs-cluster subsets: - addresses: - ip: 10.0.0.1 - addresses: - ip: 10.0.0.1
- 10. GlusterFS Volume Driver containers: - name: glusterfs image: nginx volumeMounts: - mountPath: "/mnt/glusterfs" name: glusterfsvol Mounts the volume to /mnt/glusterfs in the container’s chroot.
- 11. GlusterFS Volume Driver Pros: ● Works with existing volumes ● Shared data Cons: ● Not dynamic ● Must be managed externally ● Only shared data
- 13. Local-volume storage class kind: StorageClass apiVersion: storage.k8s.io/v1 metadata: name: myglustervol namespace: kube-system provisioner: kubernetes.io/host-path The code says: // This Provisioner is meant for // development and testing only and // WILL NOT WORK in a multi-node // cluster.
- 14. Local-volume storage class kind: StorageClass apiVersion: storage.k8s.io/v1 metadata: name: myglustervol namespace: kube-system provisioner: kubernetes.io/host-path The code says: // This Provisioner is meant for // development and testing only and // WILL NOT WORK in a multi-node // cluster.
- 15. Local-volume storage class ● Can only use /tmp/hostpath_pv ● Awkward mount ● No actual allocation restriction ● Works great! /tmp/hostpath_pv glusterfs gluster:/myvol ... /tmp/hostpath_pv/{{ uuid }} kind: PersistentVolumeClaim apiVersion: v1 metadata: name: deluge-config spec: accessModes: - ReadWriteMany resources: requests: storage: 50Mi
- 17. GlusterFS+Heketi Heketi provides a REST api for the configuration of GlusterFS which can be (and is) used by several infrastructure tools including Kubernetes. Support for GlusterFS using Heketi is part of the main kubernetes tree and has strong downstream acceptance. Heketi is the Taíno (a Caribbian aboriginal) word for “One”.
- 18. Heketi ● GlusterFS in pods ● Strongly opinionated cluster design ● Allows metered private PVCs ● Provides an excellent api interface to GlusterFS
- 19. Heketi ● GlusterFS in pods (privileged) ● Strongly opinionated cluster design ○ Whole disk ○ volume-per-PVC ● Requires prior knowledge ● Doesn’t follow best practices wrt hostnames vs IP addresses
- 20. Rook
- 21. Rook Rook is a completely cloud-native toolset to provide turnkey storage to kubernetes. It currently only does so with Ceph, but they want to add GlusterFS support and are seeking help.
- 22. Rook What I like about rook: $ helm repo add rook-alpha https://charts.rook.io/alpha $ helm install rook-alpha/rook
- 23. Rook ● Established provider of ceph storage to kubernetes ● Downstream user = community contributions! ● Enhance the user experience
- 24. Rook ● Automated decision making ● Too easy? ● Small team, needs contributions
- 25. Glusterd V2?
- 26. Questions?
- 27. Joe Julian, Samsung SDS me@joejulian.name Think about where we’re going with respect to kubernetes. Contribute to Kubernetes, Rook, Kraken. Be part of the community! ● Join the sig-storage meetings ● Hang out in #sig-storage on the kubernetes slack ● Join the rook slack ● Hang out with me in #gluster on IRC github.com/samsung-cnct/kraken github.com/kubernetes/kubernetes github.com/rook/rook Comment on the Rook + GlusterFS design document! https://goo.gl/L62Bi2