Arun Communitiy

Accessing Openstack using Rest API

arunsr3 ‎ 14.367 Visualizações

After successfully installing and administering openstack as shown in my earlier blogs(blog1, blog2 and blog3) now i have put together this blog to show how we can access some of the features using Openstack Rest API. The first step is we need to authenticate with the identity service (Keystone) and get a token which will be needed to access the other api's such as create a server, delete a server etc, note that the token will be valid for 24 hours , once it expires will need to request a new token.

First step is to update the localsrc in the openstack directory with this property

KEYSTONE_TOKEN_FORMAT=UUID

as shown in Figure 1

Figure 1

What this does is it will generate a smaller token after authentication. To run the rest api commands I used Chrome advanced REST Client as shown in figure 2

Figure 2

Here in the url area I entered the rest api url, select post option and send in a json request to get the token, I entered the username and password and the tenantName, which can be got from the Openstack horizon dashboard. After this request is submitted I got a response back with the token as seen in figure 3

Figure 3

From figure 3 I can see issue time of the token and also the token id (6a8e0a8962464f37a291035099110fd8), I will use this id in my api calls. When I get unable to authenticate exception then that means the token has expired and need to repeat the above process.

Now with this new found token id, lets try a few tasks via the api

Lets try to get a list of tenants(projects) through the api

Api is http://10.81.95.139:5000/v2.0/tenants

note the difference from the earlier one, which had tokens because we requested the tokens then. Do a get request from the client as shown in figure 4

Figure 4

As can be seen from figure 4 I have the api url and then include the token as a header value from openstack to know user is authenticated. Once this is submitted I get a json response with all the details of the tenants as shown in Figure 5

Figure 5

Lets say we need a list of all instances in the system, the url would be

http://10.81.95.139:8774/v2/09d3a0ca0ea0428abd62727c336121c5/servers

Notice the difference in the url pattern, now I access the Nova compute unlike before where I accessed the Identity service. In a minute i'll explain how to get the url's for different components in openstack.. Now look at figure 6 to see the response of the list servers call

Figure 6

I can decipher from this we have two servers running arun1 and arun, gives details about the servers aswell.

Now coming back to getting the urls of the components, login into the horizon dashboard and access the access and security option as shown in figure 7. This will list all the base api urls for openstack api's.

Figure 7

Conclusion: From this blog I can say it is fairly easy to access all the openstack features using the rest api. It is as simple as first authenticate get the token and then use the token in all other api calls as a header value as described in the blog.

Modificado em por arunsr3

Working with Openstack installed on IBM Softlayer cloud compute instance

arunsr3 ‎ 5.335 Visualizações

In my earlier blog1 and blog2 i explained how to install and manage openstack and also how to restart openstack service. Now that we have the install/manage out of the way, lets try to use the install to provision instances using the openstack user interface(UI). Open stack comes with a default image called cirros which is a small footprint linux image. I went ahead and imported fedora image as well to have a better and bigger represented image.

I will demonstrate how to provision a fedora based image virtual machine, assign a floating point ip to it and ssh to it from the public internet.

After logging into openstack i end up here as shown in figure 1 in the overview tab, let me visit the Images section to see whats available out of the box

Figure 1

Now click on Images & Snapshots from the left navigation pane, this will lead to a screen as shown in figure 2 and I can see the cirros default cloud image. This is a good starter image, however i plan to provision using fedora, the next steps will show how to add a image to openstack.

Figure 2

Click the create Image button as shown on the extreme right of figure 2 . This will popup a window as shown in figure 3 to enter details of the image to be imported.

Figure 3

I have entered all fedora image details, image location, format, public or private setting and the name of the image. Final step is to click on Create Image which will import the image into openstack and list it under the public images tab along with the cirros image as shown in figure 4.

Figure 4

Now the fun part begins, I am ready to create a few guest virtual machines. Click the launch button against the Fedora19 image as shown on the extreme right of figure 4. This will launch a popup , enter all the fields as shown in Figure 5. Make sure the Flavor option matches the size for the image, example if i were to instantiate a cirros image it would have been tiny option, but for fedora I picked small. I am not done yet, need to configure ssh so as to login after the instance is provisioned.

Figure 5

Click on the Access & Security tab and configure the public/private key as shown in figure 6. The instructions are self explanatory and no different than any ssh configuration

Figure 6

After successfully importing the keypair, click the launch button shown in figure 5, now the process begins to create a guest virtual machine . This will lead to figure 7

Figure 7

Figure 7 shows the new instance being created, please note even if the instance shows success, we have to wait until the status turns to running. Also notice the two ip addresses, one is the private ip, the management node can access the instance through this ip. The second is the public ip and we can ssh to this from the internet with the private key. I was able to associate the floating ip to the instance by clicking the associate ip from the more menu as shown in figure 8.

Figure 8

The floating ip was picked from the ip pool configured during the install of openstack, refer to earlier blog , Please take a moment to look at what is offered on the instance menu, one could associate ip as we did before, disassocaite ip, get console access to the instance through vnc, view startup logs, terminate instance etc.

Now i am left with the last step which is to confirm instance is healthy, responding to pings and i am able to ssh. If for some reason its not possible to ping, please check the security rules, the ping and ssh ports need to be opened as shown in figure 9

Figure 9

Here i have the rule to allow the instances to be pinged and also ssh. Now using any ssh client of choice, have the ssh private key handy and ssh to the instance, the user name is fedora. In this example i used putty(converted the private key generated in figure 6 to putty format using puttygen) to ssh into the instance. as shown in figure 10

Figure 10

With this i can confirm the instance is fine and i am able to ssh to it.

Conclusion: In this blog i was able to show how easy it is to create a instance and use openstack as cloud virtual machine orchestrator. This is a great tool for any developer who is working on openstack and wants to be able to debug his code, be it testing integration with openstack rest api or installation defects amd many more.

Modificado em por arunsr3

Restart services of devstack based openstack

arunsr3 ‎ 22.729 Visualizações

In my previous blog i discussed how to install devstack based openstack. Now if I need to restart individual services of openstack, in a typical openstack install I would restart the service of each component, example nova-network service, horizon etc however in devstack individual services are run as screens. First step would be to join the stack/screen as shown in figure 1

Figure 1

After joining the screen enter the following command ctrl + a + " , this will show all the devstack screens as a menu as shown in figure 2

Figure 2

Now lets say I modified the nova network config file and want to restart the service, the way I would do it is, press 9 and then cntrl C, this will stop(kill) nova network service, now rerun the last command as shown in figure 3

Figure3

Once I run the command in figure 3, nova network service will start up and the changes to nova config file takes effect. To detach from the screen and get back to the shell prompt enter the following keys on the keyboard cntrl a+d and will take me back to the shell prompt

Also at any given time to reinstall openstack, just have to run the following scripts present in the devstack directory

./unstack.sh

./stack.sh

Conclusion:

We are now able to modify openstack properties and restart individual services. Also we know how to reinstall openstack if required.

Now in my next blog will move on to use the install to create a few virtual instances using the openstack horizon userinterface.

Modificado em por arunsr3

Installing SingleSever Openstack(devstack install) on IBM SoftLayer Cloud compute instance

arunsr3 Marcações: openstack devstack softlayer ‎ 6.938 Visualizações

This week I finished installing a devstack based install of openstack on IBM softlayer Cloud compute instance. It took me quite some time to figure out all the pieces to get it successfully working. Though all this information is available on the internet, I found it was not in one place, hence I decided to write this blog to capture all the steps. Please note this install is by no means to be used for a production based Openstack deployment, this is more for developers who want to quickly get a install going and test out there application to work with Openstack, api, authentication etc. Below are the step i went through

Create a softlayer cloud compute instance(CCI) with the following configuration as shown figure 1. It is important to pick the correct version of RHEL, else the install will not work. In this case I have picked RHEL 6.0.64 version

Figure 1
VPN into SoftLayer , after the instance is created, ssh into it as root.
Devstack install does not like to be installed as root, so create a user and make sure the user is added to the sudoers file

a. useradd xyz (set user).

b. passwd xyz (set password).

c. vi /etc/sudoers, add xyz in sudo file.
Now start a new ssh session with user as xyz
Check if git is installed else yum install git

a. sudo yum install git.
git clone git://github.com/openstack-dev/devstack.git (get the openstack bits).
cd ~/devstack (assuming we ran the above command in xyz home).
One more step before running the install, if you plan on assigning a fixed ip or floating point ip range, please follow these steps, look for localrc file, if you do not find one , create one and enter the ip range as shown in figure 2, I have configured it to use Floating range. One tip is if you decide to just use the private ip range 10... which the install by default assign's then you can ignore step 8 and proceed to step 9.

Figure 2
Run the install sudo ./openstack.sh
Step 9 will take some time, runs thru a lot of scripts and will scroll by, in the end will display something like as shown below.

Horizon is now available at http://173.193.179.180/

Keystone is serving at http://173.193.179.180:5000/v2.0/

Examples on using novaclient command line is in exercise.sh

The default users are: admin and demo

The password: asdsadsadsadsadsa

This is your host ip: 173.193.179.180

stack.sh completed in 692 seconds.
Using the above details should be able to login and manage the openstack install and see a screen as shown in figure 3.

Figure 3
Conclusion: One of the things i have faced in cloud development is to have a cloud based development environment. Almost always I get a shared environment which is either down or controlled and cannot freely test on them. With this install as shown in the blog I now have a working openstack install, I can test all features of openstack, such as nova commands, run openstack rest api, create/delete instances and also make sure the created guest virtual machines are accessible through the public ip's, in my view this is a very powerful setup. In my next blog will discuss on how to manage the devstack based openstack install.