Now that we have a running OpenStack Compute environment and a machine image to use, it’s now time to spin up our first cloud instance! Let’s see how we can use the information from the nova image-list and nova flavor-list commands to reference this on the command line to launch the instance that we want.
The following steps are to be carried out on our network node under the user that has access to our OpenStack Compute credentials (as created in the Installation of command-line tools on network recipe).
Ensure you are logged in to the network node and that it has Internet access to allow us to install the required packages in our environment for running OVS and Neutron. If you created this node with Vagrant, you can execute the following command:
vagrant ssh network
Before we spin up our first instance, we must create the default security settings that define the access rights. We do this only once (or when we need to adjust these) using the nova secgroup-add-rule command under Nova client. The following set of commands gives us SSH access (port 22) from any IP address and also allows us to ping the instance to help with troubleshooting. Note the default group and its rules are always applied if no security group is mentioned on the command line.
The steps are as follows:
- With the Nova client installed, we use them by configuring our environment with the appropriate environment variables:
export OS_TENANT_NAME=cookbook export OS_USERNAME=admin export OS_PASSWORD=openstack export OS_AUTH_URL=https://192.168.100.200:5000/v2.0/ export OS_NO_CACHE=1 export OS_KEY=/vagrant/cakey.pem export OS_CACERT=/vagrant/ca.pem
- Using Nova client, we can simply add the appropriate rules using the following commands:
nova secgroup-add-rule default tcp 22 22 0.0.0.0/0 nova secgroup-add-rule default icmp -1 -1 0.0.0.0/0
Note
If there are no images available yet, follow the steps of the recipe Managing images with OpenStack Image Service in Chapter 2, Glance – OpenStack Image Service.
Now that our environment is set up correctly, we carry out the following steps to launch our first instance:
- List the images available by executing the following command:
nova image-listThis should produce an output like this:
- Then, we get the available image flavors (think of them as sizes) by executing the following command:
nova flavor-listAvailable flavors for our OpenStack installation will be listed like this:
We can specify flavor either by its ID or name.
- Since our lab environment is configured to with two networks, we will need to choose to which network to attach our instance. First, list the available networks using the following command:
neutron net-listThe available networks will be displayed like this:
- To launch our instance, we need to specify image, flavor, network, and key name information we got earlier on the command line. To launch an instance using Nova client tools, we issue the following command using the UUID of our image that is named
trusty-imageandcookbook_network_1:nova boot myInstance --image 5bfb4a6d-da77-4502-ba52-2e8e40597e96 --flavor 2 --nic net-id=0375e772-b021-425c-bc17-5a3263247fb8 --key_name demokey
You should see output like the following screenshot when you launch an instance:
- This will take a few brief moments to spin up. To check the status of your instances, issue the following commands:
nova list nova show 5971ab77-9d91-40d8-9961-d86da0945f26
- The preceding commands will give an output similar to the output of the previous command lines. However, this time it has created the instance, it is now running, and it has IP addresses assigned to it:
- After a short while, you will be able to connect to this instance. If you are using the Vagrant environment, from the
networknode, you will be able to connect to the instance using network space and SSH private key. First, get a list of network spaces using the following command:ip netnsThis will show the following example output:
qdhcp-0375e772-b021-425c-bc17-5a3263247fb8Now, connect to the instance using the following command:
sudo ip netns exec qdhcp-0375e772-b021-425c-bc17-5a3263247fb8 ssh -i demokey [email protected]
Congratulations! We have successfully launched and connected to our first OpenStack cloud instance.
After creating the default security settings, we made a note of our machine image identifier, UUID value, and then called a tool from Nova client to launch our instance. Part of that command line refers to the key pair to use. We then connect to the instance using the private key as part of that key pair generated.
How does the cloud instance know what key to use? As part of the boot scripts for this image, it makes a call back to the meta-server, which is a function of the nova-api and nova-api-metadata services. The meta-server provides a go-between that bridges our instance and the real world that the Cloud init boot process can call. In this case, it downloads a script to inject our private key into the Ubuntu user’s .ssh/authorized_keys file. We can modify which scripts are called during this boot process, and this will be covered later on.
When a cloud instance is launched, it generates a number of useful metrics and details about that instance. This is presented by the nova list and nova show commands. The nova list command shows a convenient short version listing the ID, name, status, and IP addresses of our instance.
The type of instance we chose was specified as an ID of 2 when using the nova boot command. The instance types supported can be listed by running the following command:
nova flavor-list
These flavors (specification of instances) are summarized as follows:
|
Type of instance |
Memory |
VCPUS |
Storage |
Version |
|---|---|---|---|---|
|
|
512 MB |
1 |
1 GB |
32-bit and 64-bit |
|
|
2048 MB |
1 |
20 GB |
32-bit and 64-bit |
|
|
4096 MB |
2 |
40 GB |
64-bit only |
|
|
8192 MB |
4 |
80 GB |
64-bit only |
|
|
16384 MB |
8 |
160 GB |
64-bit only |