CL110 - ch04s05

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Launching and Verifying a Non-public Instance

Objectives

After completing this section, you should be able to select and manage relevant parameters for launching a non-public, tenant instance.

Launching an Instance

A previous chapter covered how to launch an instance using the Dashboard and the unified CLI. The minimum resources needed to launch a new instance are a flavor, an image, and a network. If there is only one network defined in a project, that network is used automatically when launching an instance.

Verifying Available Resources

Use the openstack command to list and examine the available resources in Red Hat OpenStack Platform. The openstack command can list available flavors, images, instances, and networks. Administrative users can also use this command to list available projects, users, and roles. The openstack show command is used to view the details of a chosen resource. Use the information provided by this command to help launch an instance or perform changes to the Red Hat OpenStack Platform environment.

Network Verification

Some projects contain multiple resources of the same type, such as networks. The specific resource to use must be specified when launching an instance. If the user fails to specify one of the required multiple resources, the creation of the instance fails.

[user@demo ~(user)]$ openstack server create \
> --flavor default \
> --image rhel8 \
> demo-server2
Multiple possible networks found, use a Network ID to be more specific. (HTTP 409) (Request-ID: req-841a675f-c762-445d-9049-8cb5e6c6649d)

Listing all available resources can help identify the correct one to use. In the previous example, listing the networks would help find the one needed to launch the instance. The output of the following command indicates that two usable networks exist in the project.

[user@demo ~(user)]$ openstack network list \
> -c Name -c Subnets
+---------------+--------------------------------------+
| Name          | Subnets                              |
+---------------+--------------------------------------+
| demo-network1 | 38e05db4-a397-491a-a8f7-8b3220799aa2 |
| demo-network2 | 27275a69-e720-4c3c-9529-9061bb5af0af |
+---------------+--------------------------------------+

To launch an instance, you need to identify the correct network and pass it to the openstack server create command. This lets OpenStack know which resource to associate with a particular instance.

[user@demo ~(user)]$ openstack server create \
> --flavor m1.web \
> --image rhel8-web \
> --nic net-id=demo-network2 \
> --security-group demo-web \
> demo-server2

Deleting Instances

The openstack server delete command deletes OpenStack instances. You need to specify the name or ID of the instance when using this command.

[user@demo ~(user)]$ openstack server delete demo-server2

It is a good practice to list available resources, after every change made, to confirm the intended change was made. In this example, list the available instances to verify that the correct instance was deleted.

[user@demo ~(user)]$ openstack server list

Verifying a Running Instance

Red Hat OpenStack Platform provides many ways to verify running instances. This can help troubleshoot potential problems or explore current limitations. You can use the Dashboard or the unified CLI to verify instances.

If the tenant network hosting the instance is not routed for external access, then the instance cannot reach the DNS server or any external resource. If the instance has one NIC it can only be accessed by other instances on the same tenant network. You can configure an instance with multiple NICs connected to different tenant networks. In this case the instance can be accessed from multiple tenant networks.

Cloud users can use the VNC console to access an isolated instance.

Verifying the Instance

The openstack server show command displays the resources used to create the instance. This includes the network, the internal IP address, the security group, image, and flavor.

The best way to verify that an instance was created with the correct resources is to access the instance. Use the openstack console url show command to display the VNC console URL.

[user@demo ~(user)]$ openstack console url show demo-server2
+-------+-------------------------------------------------+
| Field | Value                                           |
+-------+-------------------------------------------------+
| type  | novnc                                           |
| url   | http://172.25.250.50:6080/vnc_auto.html?path=...|
+-------+-------------------------------------------------+

Use the URL to access the console of the instance. The instance must have a local user created to log in at the console. After successfully logging in, use Linux commands to confirm the configuration of the instance. For example:

Use the systemctl status httpd command to confirm that a Apache HTTPD is running.
Use the ip command to verify the network configuration.
Use the netstat command to confirm which ports services are listening on.

You can also access an instance console from the Dashboard. A user name and password are required when accessing an instance from the Dashboard.

Verifying Available Resources using the Dashboard

Log in to the Dashboard as an administrative user. Only administrative users can see flavors. View the available flavors by navigating to Admin → Compute → Flavors.

View the available networks by navigating to Project → Network → Networks. You can also look at the Network Topology tab to see the available networks.

Using the available resources from the previous steps, launch a new instance. Navigate to Project → Compute → Instances. Click Launch Instance. Enter the instance name, image, flavor, and network to create an instance. Use the up arrows to select the images, flavors, and network. When all the necessary parameters are selected, click Launch instance. If any of the required elements is missing then the Launch instance button is grayed out.

After a few seconds, verify the status of the instance.

View the instance by navigating to Project → Compute → Instances. Click the name of the instance and review the Overview, Interfaces, Log, Console, and Action Log tabs.

References

Further information is available in the Virtual Machine Instances section of the Instances and Images Guide for Red Hat OpenStack Platform at https://access.redhat.com/documentation/en-us/red_hat_openstack_platform/16.0/html-single/instances_and_images_guide/index#ch-manage_instances

Discuss Red Hat OpenStack Administration I: Core Operations for Domain Operators

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Red Hat OpenStack Administration I: Core Operations for Domain Operators (CL110)

Haley_Ruccio

1 sie 2023

Learn to operate a Red Hat® OpenStack Platform private cloud and manage domain resources to secure and deploy modern, scalable cloud applications, networks and storageRed Hat OpenStack Administration I: Core Operations for Domain Operators (CL110) teaches you how to operate and manage a production Red Hat OpenStack Platform (RHOSP) single-site overcloud. You will learn how to create secure project environments in which to provision resources and manage security privileges that cloud users need to deploy scalable cloud applications. You will learn about OpenShift integration with load balancers, identity management, monitoring, proxies, and storage. You will also develop more troubleshooting and Day 2 operations skills in this course.This course is based on Red Hat OpenStack Platform 16.1.Course content summaryStudents in the Red Hat OpenStack Administration I: Core Operations for Domain Operators (CL110) course will focus on performing both routine and specialized tasks that are necessary to manage a production OpenStack overcloud domain. Students will manage OpenStack using both web-based and command-line interfaces. Essential skills covered in the course include the following:Launch instances to satisfy various use case examples.Manage domains, projects, users, roles, and quota in a multitenant environment.Manage networks, subnets, routers, and floating IP addresses.Manage instance security with group rules and access keys.Create and manage block, object and shared storage within OpenStack.Perform instance launch customization with cloud-init.Deploy scalable applications using stack templates.Audience for this courseThis course is designed for cloud users who deploy application instances and stacks, domain operators who manage resources and security for cloud users, and any other cloud personnel interested in, or responsible for, maintaining applications on private or hybrid OpenStack clouds. Any cloud persona, or personnel with roles that include performing technology evaluation, should attend this course to learn RHOSP operation and application deployment methods.Prerequisites for this courseBecome a Red Hat Certified System Administrator (RHCSA) or demonstrate equivalent experienceIf you are not a RHCSA, you can take a skill assessment to gauge your level of knowledge.

Welcome to the Red Hat OpenStack Administration I (CL110) group in the Red Hat Learning Community!

Syed

31 lip 2023

We are excited to launch a space dedicated to the Red Hat Training course CL110! To gain the most value from this group - click the "Join Group" button in the upper right hand corner of the group home page.We encourage group members to collaborate in this group to discuss topics, ask questions, share best practices and tips, provide course feedback, and share their accomplishments as it relates to CL110.Read more about Red Hat OpenStack Administration I: Core Operations for Domain Operators here.

Revision: cl110-16.1-4c76154