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Doryd

Doryd is an out-of-tree dynamic provisioner for Docker Volume plugins that uses the StorageClass interface available in Kubernetes. Doryd needs to have access to the cluster to listen for Persistent Volume Claims against the Storage Classes that Dory governs. Doryd also depends on Dory, the FlexVolume driver for Docker Volume plugins.

Building (optional)

There are two ways provided to build Doryd. A host machine build and a fully containerized build. The containerized build require Docker 17.05 or newer on both client and daemon.

Host build

Doryd is written in Go and requires golang on your machine. The following example installs the necessary tools and builds Doryd on a RHEL 7.4 system:

sudo subscription-manager repos --enable=rhel-7-server-optional-rpms
sudo yum install -y golang make
git clone https://github.com/hpe-storage/dory.git
make gettools
make vendor
make doryd

You should end up with a doryd executable in the ./bin directory.

Optionally, you may build a doryd container:

docker build -t doryd:latest build/docker/doryd/Dockerfile .

Hint: Go is available through the EPEL repository for .rpm based distributions and a golang package is part of the official Ubuntu repositories.

Containerized build

Building Doryd in a container uses a multi-stage build and only require Docker 17.05 or newer.

docker build -t doryd:latest https://raw.githubusercontent.com/hpe-storage/dory/master/build/docker/doryd/Dockerfile.staged

Running

Doryd is available on Docker Hub and an example DaemonSet specification is available.

Prerequisities

The doryd binary needs access to the cluster via a kubeconfig file. The location may vary between distributions. The stock DaemonSet spec will assume the container default of /etc/kubernetes/admin.conf. This file needs to exist on all nodes prior to deploying the DaemonSet.

The default provisioner name is prefixed with dev.hpe.com and will listen for Persistent Volume Claims that asks for Storage Classes with provisioner: dev.hpe.com/DockerVolumeDriverName and will map against a Dory FlexVolume driver with the same provisioner. Hence it's important that the FlexVolume driver name matches up with what you name your provisioner.

A custom doryd command line could look like this:

doryd /root/.kube/cluster.conf nimblestorage.com

There should then be a Dory FlexVolume driver named nimblestorage.com/yourdrivername and Storage Classes should use provisioner: nimblestorage.com/yourdrivername.

kubectl

Deploying the default DaemonSet out-of-the-box can be accomplished with:

kubectl apply -f https://raw.githubusercontent.com/hpe-storage/dory/master/examples/ds-doryd.yaml

Add arguments to the container image if using a custom path to kubeconfig or need a different prefix.

Using

The Kubernetes documentation is good source for learning about Storage Classes, Proivsioners, Persistent Volume Claims and Persistent Volumes. The following basic examples assumes familiarity with those basic concepts. A full tutorial for Dory and Doryd is available on developer.hpe.com

Since Dory and Doryd solely relies on underlying Docker Volume plugin capabilities to provision storage, please consult the documentation for the corresponding plugin documentation.

The following example will use the dev.hpe.com/nimble FlexVolume driver to provision volumes capped at 5000 IOPS using a database optimized Performance Profile with a custom Protection Template that replicate data offsite.

kubectl create -f- <<EOF
---
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
 name: database
provisioner: dev.hpe.com/nimble
parameters:
  description: "Volume provisioned by doryd from database StorageClass"
  limitIOPS: "5000"
  perfPolicy: "SQL Server"
  protectionTemplate: "Retain-90Local-360Remote"
EOF

An end-user may then reference the Storage Class when creating a Persistent Volume Claim:

kubectl create -f- <<EOF
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: myclaim
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 500Gi
  storageClassName: database
EOF

The key here is that the end-user have no interest in knowing any underlying storage terminology. The admin may change the entire Storage Class and backend vendor without breakage for the end-user.

Licensing

Doryd is licensed under the Apache License, Version 2.0. Please see LICENSE for the full license text.