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Create a Custom OpenStack Image with Packer

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Stephanie R.
  • Updated

Learn how to create a Packer configuration file to create your own OpenStack image.

 

Requirements

You'll need an OVHcloud Public Cloud OpenStack project and a terminal.

 

Install Packer

Packer can be downloaded from the official website (currently here ) and you'll need to unzip it.

For Linux 64bits

wget https://releases.hashicorp.com/packer/1.3.1/packer_1.3.1_linux_amd64.zip
unzip packer_1.3.1_linux_amd64.zip

 

Install jq

jq is a command line tool for parsing JSON document. It'll be used to automate the configuration file creation.

apt-get install jq

 

Fetch your openrc.sh configuration

From OVHcloud Control Panel, fetch your openrc.sh configuration file. You can fetch it from OpenStack menu entry in the left panel and under the ... button on the right Download OpenStack's RC file. You might need to create an OpenStack user before.

 

Install openstack command line client

The easier way is to use a python virtual environment:

python3 -m venv venv3 # creates a virtualenv named venv3
. ./venv3/bin/activate # enter the virtualenv
pip install --upgrade pip
pip install python-openstackclient

or install your distribution package apt-get install python-openstackclient.

 

Verification

Sourcing the openrc.sh configuration file retrieved before, try your local setup with:

. ./openrc.sh
openstack token issue

 

Packer configuration

First, source your openrc.sh file with:

. ./openrc.sh

Next, let's find some needed ID. You'll need the ID of the image, flavor and network. We'll build our image from Ubuntu 16.04 on a vps-ssd-1 hardware, with an interface connected on a public network Ext-Net.

SOURCE_ID=`openstack image list -f json | jq -r '.[] | select(.Name == "Ubuntu 16.04") | .ID'`
FLAVOR_ID=`openstack flavor list -f json | jq -r '.[] | select(.Name == "vps-ssd-1") | .ID'`
NETWORK_ID=`openstack network list -f json | jq -r '.[] | select(.Name == "Ext-Net") | .ID'`
For FLAVOR_ID, you can directly use the name, e.g. vps-ssd-1

Finaly, create a packer.json file:

cat > packer.json <<EOF
{
    "builders": [
        {
            "type": "openstack",
            "username": "$OS_USERNAME",
            "password": "$OS_PASSWORD",
            "identity_endpoint": "$OS_AUTH_URL",
            "region": "$OS_REGION_NAME",
            "tenant_id": "$OS_TENANT_ID",
            "image_name": "My Custom Image",
            "ssh_username": "ubuntu",
            "source_image": "$SOURCE_ID",
            "flavor": "$FLAVOR_ID",
            "ssh_ip_version": "4",
            "networks": [
                "$NETWORK_ID"
            ]
        }
    ],
    "provisioners": [
        {
            "script": "setup_vm.sh",
            "type": "shell"
        }
    ]
}
EOF

In the last selection of the configuration file, we specify a setup_vm.sh shell script to be run.

#!/bin/sh

set -ex

if [ `id -u` -ne 0 ]; then
     sudo $0
    exit 0
fi

## your custom code below
apt-get install git
git clone ...

 

Building the image

Using the configuration file created above, check it and build the image with:

packer validate packer.json
packer build packer.json

You should have a new image available. You can check with:

openstack image list | grep 'My Custom Image'
TIP: To enable debug information: export PACKER_LOG=1

 

Go further

For more information and tutorials, please see our other Public Cloud support guides or explore the guides for other OVHcloud products and services.

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