Creating openstack new security group, and allowing inbound port

To see existing security group
$ openstack security group list

To create a new security group named ssh-allow
$ openstack security group create  ssh-allow

To allow port 22 inbound (ingress)
$ openstack security group rule create --ingress --proto tcp --dst-port 22 ssh-allow

To see if our port allowance is successfully implemented (use --fit-width to format the output properly)
$ openstack security group show ssh-allow --fit-width

Creating image from a running instance

Sometimes we want to spawn off a few new instances, with the same spec and operating systems, but we do not want to go through the hassle of setting up each OS manually, and then update it one by one. In order to do that efficiently, openstack provides a very good way, which is to create an image from a running instance, and this image can be used to spawn off new instances afterwards.

Before we turn any instance to an image, we need to know its instance ID

$ openstack server list

We can then create an image from the above instance ID

$ openstack server image create --name centos7-updated-20180525 21e78f23-8b67-423a-9622-d46c8487f829

To make sure our image is created correctly, check using:

$ openstack image list

To create a new instance from the image, please refer here

Creating a new instance on openstack

In order to create new instance (it is called server in openstack command), you need to know beforehand a few information to feed to the create instance command. Refer below for those information:

check available flavor

$ openstack flavor list

check available images

$ openstack image list

check available network

$ openstack network list

check available security group

$ openstack security group list

check available keypair

$ openstack keypair list

Once you get all the above information, to create the new instance, just use below command, providing the above information as option to openstack server create command

$ openstack server create \

--image centos-7-20180520 \

--key-name my-keypair \

--flavor m1.medium \

--security-group defaults \

--network private-140 \

thenewinstancename

To check whether your new instance has been created and active:

$ openstack server list