Cloud Storage with Red Hat Ceph Storage
In this classroom environment, your primary system for hands-on activities is workstation. The workstation virtual machine (VM) is the only system with a graphical desktop, which is required for using a browser to access web-based tools. You should always log in directly to workstation first. From workstation, use ssh for command-line access to all other VMs. Use a web browser from workstation to access the Red Hat Ceph Storage web-based dashboard and other graphical tools.
As seen in Figure 0.1, all VMs share an external network, 172.25.250.0/24, with a gateway of 172.25.250.254 (bastion). External network DNS and container registry services are provided by utility.
Additional student VMs used for hands-on exercises include clienta, clientb, serverc, serverd, servere, serverf, and serverg. All ten of these systems are in the lab.example.com DNS domain.
All student computer systems have a standard user account, student, which has the password student. The root password on all student systems is redhat.
Table 1. Classroom Machines
| Machine name | IP addresses | Role |
|---|---|---|
| workstation.lab.example.com | 172.25.250.9 | Graphical student workstation |
| clienta.lab.example.com | 172.25.250.10 | Client "A" as cluster client and admin node |
| clientb.lab.example.com | 172.25.250.11 | Client "B" cluster client |
| serverc.lab.example.com | 172.25.250.12 | Server "C" cluster storage node |
| serverd.lab.example.com | 172.25.250.13 | Server "D" cluster storage node |
| servere.lab.example.com | 172.25.250.14 | Server "E" cluster storage node |
| serverf.lab.example.com | 172.25.250.15 | Server "F" second cluster storage node |
| serverg.lab.example.com | 172.25.250.16 | Server "G" spare cluster storage node |
| utility.lab.example.com | 172.25.250.17 | Utility services such as DNS and container registry |
| classroom.example.com | 172.25.254.254 | The classroom materials and content server |
| bastion.lab.example.com | 172.25.250.254 | Router to link VMs to central servers |
The environment uses the classroom server as a NAT router to the outside network, and as a file server using the URLs content.example.com and materials.example.com, serving course content for certain exercises. Information on how to use these servers is provided in the instructions for those activities.
Your classroom environment comes with two Ceph storage clusters installed.
The primary Ceph cluster is composed of serverc, serverd, and servere.
The secondary Ceph cluster is composed of serverf.
The clienta.lab.example.com server is installed with the cephadm container and it has the required configuration to manage the primary Ceph cluster.
The serverf.lab.example.com server is installed with the cephadm container and it has the required configuration to manage the secondary Ceph cluster.
You can reset your classroom environment to set all of your classroom nodes back to their beginning state when the classroom was first created. Resetting allows you to clean your virtual machines, and start exercises over again. It is also a simple method for clearing a classroom issue which is blocking your progress and is not easily solved. Some chapters, such as chapters 02, 12, and 14, might ask you to reset your classroom to ensure you work on a clean environment. It is highly recommended to follow this instruction.
When your lab environment is first provisioned, and each time you restart the lab environment, the monitor (MON) services might fail to properly initialize and can cause a cluster warning message.
On your Red Hat Online Learning cloud platform, this behavior is caused by the random order in which complex network interfaces and services are started.
This timing issue does not occur in production Ceph storage cluster environments.
To resolve the cluster warning, use the ceph orch restart mon command to restart the monitor services, which should then result in a HEALTH_OK cluster state.
You are assigned remote computers in a Red Hat Online Learning classroom. Self-paced courses are accessed through a web application hosted at . If your course is an instructor-led virtual training, you will be provided with your course location URL. Log in to this site using your Red Hat Customer Portal user credentials.
Controlling the Virtual Machines
The virtual machines in your classroom environment are controlled through web page interface controls. The state of each classroom virtual machine is displayed on the Lab Environment tab.
Table 2. Machine States
| Virtual Machine State | Description |
|---|---|
| building | The virtual machine is being created. |
| active | The virtual machine is running and available. If just started, it may still be starting services. |
| stopped | The virtual machine is completely shut down. Upon starting, the virtual machine boots into the same state as it was before it was shut down. The disk state is preserved. |
Table 3. Classroom Actions
| Button or Action | Description |
|---|---|
| Create the ROLE classroom. Creates and starts all of the virtual machines needed for this classroom. | |
| The ROLE classroom virtual machines are being created. Creates and starts all of the virtual machines needed for this classroom. Creation can take several minutes to complete. | |
| Delete the ROLE classroom. Destroys all virtual machines in the classroom. All work saved on that system's disks is lost. | |
| Start all virtual machines in the classroom. | |
| All virtual machines in the classroom are starting. | |
| Stop all virtual machines in the classroom. |
Table 4. Machine Actions
| Button or Action | Description |
|---|---|
Connect to the system console of the virtual machine in a new browser tab.
You can log in directly to the virtual machine and run commands, when required.
Normally, log in to the workstation virtual machine only, and from there, use ssh to connect to the other virtual machines.
| |
| → | Start (power on) the virtual machine. |
| → | Gracefully shut down the virtual machine, preserving disk contents. |
| → | Forcefully shut down the virtual machine, while still preserving disk contents. This is equivalent to removing the power from a physical machine. |
| → | Forcefully shut down the virtual machine and reset the disk to its initial state. All work saved on that system's disks is lost. |
At the start of an exercise, if instructed to reset a single virtual machine node, click → for only the specific virtual machine.
At the start of an exercise, if instructed to reset all virtual machines, click → on every virtual machine in the list.
If you want to return the classroom environment to its original state at the start of the course, you can click to remove the entire classroom environment. After the lab has been deleted, you can click to provision a new set of classroom systems.
Warning
The operation cannot be undone. All work you have completed in the classroom environment will be lost.
The Auto-stop and Auto-destroy Timers
The Red Hat Online Learning enrollment entitles you to a set allotment of computer time. To help conserve your allotted time, the ROLE classroom uses timers, which shut down or delete the classroom when the appropriate timer expires.
To adjust the timers, locate the two buttons at the bottom of the course management page. Click the auto-stop button to add another hour to the auto-stop timer. Click the auto-destroy button to add another day to the auto-destroy timer. There is a maximum for auto-stop at 11 hours, and a maximum auto-destroy at 14 days. Be careful to keep the timers set while you are working, so as to not have your environment unexpectedly shut down. Be careful not to set the timers unnecessarily high, which could waste your subscription time allotment.
