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OpenStack API Tutorial

Introduction to OpenStack CLI

The OpenStack command line interface (CLI) is only one way to interact with OpenStack’s RESTful API. In this exercise we will use the command line clients installed on Jetstream instances to OpenStack entities; e.g. images, instances, volumes, objects, networks, etc.

We'll be using a host that's been prepped with a recent OpenStack python client and the appropriate credentials. Typically you would need to have the CLI clients installed. The latest client is available from https://pypi.python.org/pypi/python-openstackclient

Instructions for installing clients for multiple operating systems is here: https://docs.openstack.org/mitaka/user-guide/common/cli_install_openstack_command_line_clients.html

Note that many people prefer installing in a virtualenv. An example of that would be:

[user@localhost]$ virtualenv ~/venv
[user@localhost]$ source ~/venv/bin/activate
(venv)user@localhost$ pip install python-openstackclient

Also note that we will NOT be installing the clients for this tutorial.

Some background getting started Jetstream Documentation

Getting started with the Jetstream’s OpenStack API http://wiki.jetstream-cloud.org/Using+the+Jetstream+API

Notes about accessing Jetstream’s OpenStack API http://wiki.jetstream-cloud.org/After+API+access+has+been+granted

SDKs for programmatically accessing OpenStack’s APIs https://docs.openstack.org/openstacksdk/latest/user/

openrc.sh for Jetstream’s OpenStack API http://wiki.jetstream-cloud.org/Setting+up+openrc.sh

Getting started with the hands on portion of the tutorial

Insuring that your credentials are in order

Jetstream is an XSEDE resource and you must have an XSEDE account before you can use it either via the Atmosphere user interface or the OpenStack API. The following steps must work before proceeding; specifically, accessing the Horizon dashboard. If you cannot login to the Horizon dashboard, nothing else will work. When you first get API access on Jetstream, that's typically how we recommend people test their credentials.

Access Openstack Client Server

To access the client server, use your provided username and password, and log in to

ssh your_training_user@tutorial.jetstream-cloud.org

You'll actually want to have TWO connections to this host. The reasons will be more obvious later.

You may experience a delay after typing in your password - this is normal! Don't cancel your connection.

Configure openstack client

First, double-check the openrc.sh with your training account info - the file already exists in your home directory. Normally you'd have to create your own -- refer to http://wiki.jetstream-cloud.org/Setting+up+openrc.sh

[Tutorial] train60 ~--> cat ./openrc.sh
export OS_PROJECT_DOMAIN_NAME=tacc 
export OS_USER_DOMAIN_NAME=tacc 
export OS_PROJECT_NAME=TG-CDA170005 
export OS_USERNAME=SET_ME
export OS_PASSWORD='REDACTED' 
export OS_AUTH_URL=ADD_END_POINT
export OS_IDENTITY_API_VERSION=3

In the real world you will not want to save your password in a file. A much more secure way to set OS_PASSWORD is to read it from the command line when the openrc is sourced. E.g.

echo "Please enter your OpenStack Password: "
read -sr OS_PASSWORD_INPUT
export OS_PASSWORD=$OS_PASSWORD_INPUT

Next, add these environment variables to your shell session:

source openrc.sh

Ensure that you have working openstack client access by running:

openstack image list | grep JS-API-Featured

A few notes about openstack commands

Command structure

  • openstack NOUN VERB PARAMETERS
  • openstack help [NOUN [VERB [PARAMETER]]]
  • openstack NOUN VERB -h will also produce the help documentation
  • Common NOUNs include image, server, volume, network, subnet, router, port, etc.
  • Common verbs are list, show, set, unset, create, delete, add, remove, etc.
  • Two commonly used verbs are list and show
  • list will show everything that your project is allowed to view
  • show takes a name or UUID and shows the details of the specified entity

E.g.

openstack image list
openstack image show JS-API-Featured-CentOS7-May-20-2019
openstack image show 368d1a0d-cc90-4190-9225-a16004deaad3

You can also make the output look nicer in your terminal with the --fit-width option:

openstack image show JS-API-Featured-CentOS7-May-20-2019 --fit-width

You can make that permanent by adding

export CLIFF_FIT_WIDTH=1

to your environment.

It's also important to note that the OpenStack CLI client offers help for the commands

E.g.

openstack help image
openstack help image show

Names verses UUIDs

  • Names and Universally Unique Identifier (UUID) are interchangeable on the command line
  • IMPORTANT POINT TO NOTE: OpenStack will let you name two or more entities with the same names. If you run into problems controlling something via its name, then fall back to the UUID of the entity.
  • Once you have two entities with the same name, your only recourse is to use the UUID

Creating the cyberinfrastructure and booting your first instance

It is informative to follow what’s happening in the Horizon dashboard as you execute commands. Keep in mind that in OpenStack everything is project based. Everyone in this tutorial is in the same OpenStack project. In the Horizon dashboard you will see the results of all the other students commands as they execute them. You can also affect other objects in your project, so tread carefully and don't delete someone else's work!

What we’re going to do

  • Create security group and add rules
  • Create and upload ssh keys
  • Create and configure the network (this is only done once)
  • Start an instance
  • Log in and take a look around
  • Shutdown the instance
  • Dismantle what we have built

Create security group and adding rules to the group

By DEFAULT, the security groups on Jetstream (OpenStack in general) are CLOSED - this is the opposite of how firewalls typically work (completely OPEN by default). If you create a host on a new allocation without adding it to a security group that allows access to some ports, you will not be able to use it!

Create the group that we will be adding rules to

openstack security group create --description "ssh & icmp enabled" ${OS_USERNAME}-global-ssh

Create a rule for allowing ssh inbound from an IP address

openstack security group rule create --protocol tcp --dst-port 22:22 --remote-ip 0.0.0.0/0 ${OS_USERNAME}-global-ssh

Create a rule that allows ping and other ICMP packets

openstack security group rule create --proto icmp ${OS_USERNAME}-global-ssh

*There's a reason to allow icmp. It's a contentious topic, but we recommend leaving it open. http://shouldiblockicmp.com/

Optional rule to allow connectivity within a mini-cluster; i.e. if you boot more than one instance, this rule allows for communications amongst all those instances.

openstack security group rule create --proto tcp --dst-port 1:65535 --remote-ip 10.0.0.0/24 ${OS_USERNAME}-global-ssh
openstack security group rule create --proto udp --dst-port 1:65535 --remote-ip 10.0.0.0/24 ${OS_USERNAME}-global-ssh

A better (more restrictive) example might be: We won't need this today

openstack security group rule create --proto tcp --dst-port 1:65535 --remote-ip 10.X.Y.0/24 ${OS_USERNAME}-global-ssh
openstack security group rule create --proto udp --dst-port 1:65535 --remote-ip 10.X.Y.0/24 ${OS_USERNAME}-global-ssh

Look at your security group (optional)

openstack security group show ${OS_USERNAME}-global-ssh

Adding/removing security groups after an instance is running (you don't have a server running yet so these will produce an error -- it's just information you might need later).

openstack server add    security group ${OS_USERNAME}-api-U-1 ${OS_USERNAME}-global-ssh
openstack server remove security group ${OS_USERNAME}-api-U-1 ${OS_USERNAME}-global-ssh

Note: that when you change the rules within a security group you are changing them in real-time on running instances. When we boot the instance below, we will specify which security groups we want to associate to the running instance.

Access to your instances will be via ssh keys

If you do not already have an ssh key we will need to create on. For this tutorial we will create a passwordless key. In the real world, you would not want to do this

ssh-keygen -b 2048 -t rsa -f ${OS_USERNAME}-api-key -P ""

Upload your key to OpenStack

openstack keypair create --public-key ${OS_USERNAME}-api-key.pub ${OS_USERNAME}-api-key

Look at your keys (optional)

openstack keypair list

**If you want to be 100% sure, you can show the fingerprint of your key with the following command. It's a good habit to be in.

ssh-keygen -l -E md5 -f ${OS_USERNAME}-api-key

Create and configure the network (this is usually only done once)

Create the network

openstack network create ${OS_USERNAME}-api-net

List the networks; do you see yours?

openstack network list

Create a subnet within your network.

If you want to list the subnets that have been created, just in case

openstack subnet list

Then create your subnet - notice that you can all use the same 10.0.0.0 network. You can use a different address space, but you don't have to.

openstack subnet create --network ${OS_USERNAME}-api-net --subnet-range 10.0.0.0/24 ${OS_USERNAME}-api-subnet1

Create a router

openstack router create ${OS_USERNAME}-api-router

Attach your subnet to the router

openstack router add subnet ${OS_USERNAME}-api-router ${OS_USERNAME}-api-subnet1

Attach your router to the public (externally routed) network

openstack router set --external-gateway public ${OS_USERNAME}-api-router

*Note: You cannot attach an instance directly to the public router. This was a conscious design decision.

Note the details of your router

openstack router show ${OS_USERNAME}-api-router

Stopping and smelling the roses

Well, looking at the changes in Horizon -

Open a new tab or window to

with your tg???? id and password (in your openrc.sh file), to monitor your build progress on the Horizon interface. You will also be able to view other trainees instances and networks - PLEASE do not delete or modify anything that isn't yours!

And let's talk a bit here about Horizon, what it is, and why we're using the CLI and not this GUI...

Start an instance

Note the flavors (sizes) of instances that create

openstack flavor list

Note the possible images that you can use on the API side of Jetstream.

openstack image list --limit 500 | grep JS-API-Featured

*Note: Images without the JS-API- string are destined to be boot via Atmosphere. Atmosphere runs various scripts during the boot process. If you are booting via the API then these scripts will not get executed and the booted instance may (probably) will not be usable. We're going to use a prepped cluster image.

Time to boot your instance -- please note that the image will change! They are updated and named with the date.

openstack server create ${OS_USERNAME}-headnode \
--flavor m1.small \
--image JS-API-Featured-CentOS7-Latest \
--key-name ${OS_USERNAME}-api-key \
--security-group ${OS_USERNAME}-global-ssh \
--nic net-id=${OS_USERNAME}-api-net \
--user-data cloud.cfg \
--wait

*Note that ${OS_USERNAME}-headnode is the name of the running instance. A best practice for real usage is to pick a name that helps you identify that server. Each instance you boot should have a unique name; otherwise, you will have to control your instances via the UUID

*Note on patching

*Note on what all of those switches really mean

You can actually see the console just as you would if you were watching it boot -- use the UID of the server you created:

openstack console log show UID_of_your_instance

Create an IP address…

openstack floating ip create public

…then add that IP address to your running instance. Substitute the actual IP number you just got for the <your.ip.number.here>

openstack server add floating ip ${OS_USERNAME}-headnode <your.ip.number.here>

Is the instance reachable? Substitute the actual IP number you got for the <your.ip.number.here>

ping <your.ip.number.here>

In your second terminal window and/or with your favorite ssh client (if you use an external ssh client, you'll need to get that private key to put in it!). Substitute the actual IP number you got for the <your.ip.number.here>

ssh -i ${OS_USERNAME}-api-key centos@<your.ip.number.here> 

*or if you were using an Ubuntu image*

ssh -i ${OS_USERNAME}-api-key ubuntu@<your.ip.number.here>

A brief look at volumes

Creating a volume:

Back in your openstack window, do the following:

openstack volume create --size 10 ${OS_USERNAME}-10GVolume

Now, add the new storage device to your VM:

openstack server add volume ${OS_USERNAME}-headnode ${OS_USERNAME}-10GVolume

Let's ssh in and get the volume working (if you're not still logged in via the other window). Substitute the actual IP number you just got for the <your.ip.number.here>.

ssh -i ${OS_USERNAME}-api-key centos@<your.ip.number.here> 

*or if you were using an Ubuntu image*

ssh -i ${OS_USERNAME}-api-key ubuntu@<your.ip.number.here>

Become root on your VM: (otherwise, you'll have to preface much of the following with sudo)

sudo su -

Find the new volume on the headnode with (most likely it will mount as sdb). The command is:

dmesg | grep sd

And the output should look something like this:

root@tg455656-headnode ~]# dmesg | grep sd
[    1.715421] sd 2:0:0:0: [sda] 16777216 512-byte logical blocks: (8.58 GB/8.00 GiB)
[    1.718439] sd 2:0:0:0: [sda] Write Protect is off
[    1.720066] sd 2:0:0:0: [sda] Mode Sense: 63 00 00 08
[    1.720455] sd 2:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[    1.725878]  sda: sda1
[    1.727563] sd 2:0:0:0: [sda] Attached SCSI disk
[    2.238056] XFS (sda1): Mounting V5 Filesystem
[    2.410020] XFS (sda1): Ending clean mount
[    7.997131] Installing knfsd (copyright (C) 1996 okir@monad.swb.de).
[    8.539042] sd 2:0:0:0: Attached scsi generic sg0 type 0
[    8.687877] fbcon: cirrusdrmfb (fb0) is primary device
[    8.719492] cirrus 0000:00:02.0: fb0: cirrusdrmfb frame buffer device
[  246.622485] sd 2:0:0:1: Attached scsi generic sg1 type 0
[  246.633569] sd 2:0:0:1: [sdb] 20971520 512-byte logical blocks: (10.7 GB/10.0 GiB)
[  246.667567] sd 2:0:0:1: [sdb] Write Protect is off
[  246.667923] sd 2:0:0:1: [sdb] Mode Sense: 63 00 00 08
[  246.678696] sd 2:0:0:1: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[  246.793574] sd 2:0:0:1: [sdb] Attached SCSI disk

Create a new filesystem on the device (from the VM):

mkfs.ext4 /dev/sdb

Create a directory for the mount point and mount it (on the VM):

mkdir /export
mount /dev/sdb /export
df -h

Let's add it to the /etc/fstab so it's persistent:

vi /etc/fstab 

you can use nano or emacs, but I'll judge you

add this line:

/dev/sdb /export ext4 defaults 1 2

DO NOT DO THESE -- THIS IS FOR INFORMATION PURPOSES ONLY

Putting our instance into a non-running state

Reboot the instance (shutdown -r now).

openstack server reboot ${OS_USERNAME}-headnode

or

openstack server reboot ${OS_USERNAME}-headnode --hard

Stop the instance (shutdown -h now). Note that state is not retained and that resources are still reserved on the compute host so that when you decide restart the instance, resources are available to activate the instance.

openstack server stop ${OS_USERNAME}-headnode
openstack server start ${OS_USERNAME}-headnode

Put the instance to sleep; similar to closing the lid on your laptop. Note that resources are still reserved on the compute host for when you decide restart the instance

openstack server suspend ${OS_USERNAME}-headnode
openstack server resume  ${OS_USERNAME}-headnode

Shut the instance down and move to storage. Memory state is not maintained. Ephemeral storage is maintained. Note that resources are still reserved on the compute host for when you decide restart the instance

openstack server shelve ${OS_USERNAME}-headnode
openstack server unshelve ${OS_USERNAME}-headnode

For further investigation… A tutorial was presented at the PEARC17 conference on how to build a SLURM HPC cluster with OpenStack - https://github.com/ECoulter/Tutorial_Practice

The tutorial assumes that a node at IP 149.165.157.95 is running that you need to login to as a first step. (Similar to this exercise.) This node was provided as an easy way to run the class and its only purpose was to provide a host with the openstack CLI clients installed. You can safely skip this step and proceed with executing the openstack commands you see in the tutorial.

There are also two projects going on for virtual clustering:

Dismantling what we have built

Note that infrastructure such as networks, routers, subnets, etc. only need to be created once and are usable by all members of the project. These steps are included for completeness. And, to clean up for the next class.

Let's clean up the volume (from the instance):

cd /
umount /export

Do this from the shell host:

openstack server remove volume ${OS_USERNAME}-headnode ${OS_USERNAME}-10GVolume
openstack volume delete ${OS_USERNAME}-10GVolume

Remove the IP from the instance. Substitute the actual IP number you got for the <your.ip.number.here>.

openstack server remove floating ip ${OS_USERNAME}-headnode <your.ip.number.here>

Return the IP to the pool. Substitute the actual IP number you got for the <your.ip.number.here>

openstack floating ip delete <your.ip.number.here>

Delete the instance

openstack server delete ${OS_USERNAME}-headnode

Unplug your router from the public network

openstack router unset --external-gateway ${OS_USERNAME}-api-router

Remove the subnet from the network

openstack router remove subnet ${OS_USERNAME}-api-router ${OS_USERNAME}-api-subnet1

Delete the router

openstack router delete ${OS_USERNAME}-api-router

Delete the subnet

openstack subnet delete ${OS_USERNAME}-api-subnet1

Delete the network

openstack network delete ${OS_USERNAME}-api-net

Delete the security group

openstack security group delete ${OS_USERNAME}-global-ssh

Delete the key pair

openstack keypair delete ${OS_USERNAME}-api-key

*Meta: Goo.gl link: https://is.gd/jYsnyJ

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