# VLANs Management

## VLANs

A VLAN is a numbered network segment used to separate traffic inside a
switch domain.
In zCompute, a VLAN helps organize network connectivity by linking a VLAN
tag to a specific switch domain, and then associating that VLAN with an
account, project, or network as needed.

Use the **Account Networking > VLANs Management** screen to manage VLANs
for accounts, see where a VLAN is assigned, and to perform lifecycle tasks
such as adding, assigning, releasing, or checking VLAN connectivity.

### VLAN creation and allocation flow

![dvs-vlan-creation-flow](media/dvs-vlan-creation-flow.png)

1. Zadara Operations creates the system VLAN pool, and adds or removes VLANs
   in the pool.
2. MSPs or Zadara Operations allocate VLANs from the system VLAN pool to
   an account’s VLAN pool.
3. The account administrator (MSP or tenant) assigns VLANs from
   the account’s VLAN pool to a project’s VLAN pool.
4. The account administrator can create a DVS network by allocating a VLAN
   to a DVS project, and associating a VM instance with the project’s network.

### VLAN release and deletion flow

![dvs-vlan-release-flow](media/dvs-vlan-release-flow.png)

1. The account administrator (MSP or tenant) can release a VLAN that is
   allocated to a network, back to the project’s VLAN pool, by deleting
   its network.
2. The account administrator can release VLANs that are not allocated to a
   network, from a project’s VLAN pool back into the account’s VLAN pool.
3. Zadara Operations can release VLANs that are not allocated to a network,
   from an account’s VLAN pool back into the system VLAN pool.
4. Zadara Operations can remove a VLAN from the system pool.

## Managing VLANs

### Viewing VLANs

To view the VLANs that are available:

1. Go to **Account Networking > VLANs Management**.

   The **VLANs Management** screen opens in **List** view.
2. Review the VLANs table.

   The table shows these fields:
   * **VLAN**

     The VLAN tag ID.

     Use it to identify the VLAN.
   * **Account**

     The account that owns the VLAN assignment.
   * **Project**

     The project that uses the VLAN.
   * **Network**

     The linked network.

     Use it to see whether the VLAN is already tied to a network.
   * **VMs**

     The number of VMs that use the linked network.
   * **Switch Domain**

     The switch domain linked to the VLAN.

### Adding VLANs

A single VLAN, multiple individual VLANs, a range and multiple ranges of
VLANs can be created in one request.

Assigning the VLANs to an account and project can be configured when adding
new VLANs, or can be left to be assigned later.

To configure new VLAN entries:

1. Go to **Account Networking > VLANs Management**.

   The **VLANs Management** screen opens in **List** view.
2. From the top toolbar, select **+ Add**.

   The **Add VLANs** dialog opens.
   1. Enter the VLAN ranges:

   * **Switch Domain**

     From the dropdown, select the switch domain where the VLAN range
     will be created.

     Required.
   * **Account**

     From the dropdown, select the VLAN account pool that the VLANs can
     be assigned to.

     If this is not entered, it can be assigned later.
   * **Project**

     From the dropdown, select the project that can use the VLANs.

     The project list depends on the selected account.

     If this is not entered, it can be assigned later.
   * **VLAN Range**

     The section that defines one or more VLAN tag ranges to create.
     * **From**

       The first VLAN tag in the range.

       Required.
     * **to**

       The last VLAN tag in the range.

       Required.
     * For an additional range, select **Add**, and enter the VLAN
       range.
     * Selecting the **Delete row** icon removes the current VLAN
       range row from the list in the request.

   To confirm creating the VLANs range, select **Ok**.

### Assigning VLANs

A single VLAN or multiple VLANs can be assigned to an account or project
in a single **Assign** request.

To select and assign VLANs to an account or project:

1. Go to **Account Networking > VLANs Management**.

   The **VLANs Management** screen opens in **List** view.
2. To select the VLANs to assign, mark their checkboxes.

   The **Assign** option is enabled on the top toolbar.
3. From the top toolbar, select **Assign**.

   The **Assign VLANs** dialog opens, prompting for the following:
   * **Account**

     From the dropdown, select the account pool that the VLAN will be
     assigned to.

     Required.
   * **Project**

     From the dropdown, select the project that will use the selected
     VLAN.

     The project list depends on the selected account.

   To confirm assigning the VLAN, select **Ok**.

### Removing VLANs

Use this action to remove one or more VLANs from the VLAN pool.

A VLAN cannot be removed when it is linked to a network.

To select VLANs to remove:

1. Go to **Account Networking > VLANs Management**.

   The **VLANs Management** screen opens in **List** view.
2. To select the VLANs to remove, mark their checkboxes.

   The **Remove** option is enabled on the top toolbar.
3. From the top toolbar, select **Remove**.

   The **Remove VLANs** dialog opens, displaying the VLANs selected
   for removal.

   To confirm removing the selected VLANs from the VLAN pool, select **Ok**.

### Releasing VLANs from an account

Use this action to release a VLAN from an account’s VLAN pool.

This action is enabled only when the VLAN is assigned to an account and is
not assigned to a project.

To select a VLAN to release from an account:

1. Go to **Account Networking > VLANs Management**.

   The **VLANs Management** screen opens in **List** view.
2. To select the VLAN to release from an account, mark its checkbox.

   The **Release From Account** option is enabled on the top toolbar.
3. From the top toolbar, select **Release From Account**.

   The **Release VLAN From Account** dialog opens, displaying the **Name**
   and **ID** of the VLAN selected for release, and the **Account** from
   which to release it.

   To confirm releasing the selected VLAN from the account, select **Ok**.

### Releasing VLANs from a project

Use this action to release a VLAN from a project’s VLAN pool.

This action is available only when the VLAN is assigned to a project and
is not linked to a network.

To select a VLAN to release from a project:

1. Go to **Account Networking > VLANs Management**.

   The **VLANs Management** screen opens in **List** view.
2. To select the VLAN to release from a project, mark its checkbox.

   The **Release From Project** option is enabled on the top toolbar.
3. From the top toolbar, select **Release From Project**.

   The **Release VLAN From Project** dialog opens, displaying the
   **ID** of the VLAN selected for release, and the **Project** from
   which to release it.

   To confirm releasing the selected VLAN from the project, select **Ok**.

### Releasing VLANs from a network

To release a VLAN from a network, whether a direct subnet or a DVS network,
deleting the network releases its assigned VLAN back to the project pool.

### Checking VLANs

Use this action to run a VLAN connectivity check.

**Check VLAN** tests whether selected nodes can communicate with each other
on the chosen VLAN. It shows the result as a pass/fail matrix, plus an
overall **Connected**, **Not Connected**, or **Partially Connected**
summary.

The action is available only when at least two nodes are present.

The check uses the VLAN’s switch domain.

To select VLANs to check:

1. Go to **Account Networking > VLANs Management**.

   The **VLANs Management** screen opens in **List** view.
2. To select the VLANs to check, mark their checkboxes.

   The **Check VLAN** option is enabled on the top toolbar.
3. From the top toolbar, select **Check VLAN**.

   The **Check VLAN** dialog opens.

   Enter:
   * **MTU**

     The packet size that the check uses.

     Valid range: 1500 (default) to 16000.
   * **Nodes**

     The nodes that take part in the check.

     Select the nodes to test.

   Confirm proceeding with the connectivity test.

   The test results are displayed as a pass/fail matrix, plus an overall
   **Connected**, **Not Connected**, or **Partially Connected** summary.

## Recommended best practices

* Review the **Network** column before you remove or release a VLAN.
* Review the **Project** and **Account** columns before you change VLAN
  ownership.
* Review the **Switch Domain** value to confirm that you are working on
  the correct VLAN context.
* Add VLAN ranges carefully to avoid overlap or incorrect tag entry.
* Run **Check VLAN** before and after a change when at least two nodes
  are available.
* Keep the **MTU** value within the supported range for the check.

## Troubleshooting

### You cannot assign a VLAN

Check whether the **Account** field is selected.

If the **Project** list shows no projects, verify that the selected
account has available projects.

### You cannot add VLANs

Check that **Switch Domain**, **From**, and **to** are completed.

If you add more than one range, review each row before you save.

### You cannot remove a VLAN

A VLAN cannot be removed when it is linked to a network.

Check the **Network** column. If a network is shown, remove the network
dependency first.

### You cannot release a VLAN from a project

The project release action is disabled when the VLAN is not assigned to
a project or when it is linked to a network.

Check the **Project** and **Network** columns before you try again.

### You cannot release a VLAN from an account

The account release action is shown only when the VLAN is assigned to an
account and is not assigned to a project.

Check the row values to confirm the current assignment state.

### You cannot run Check VLAN

The check action requires at least two nodes.

If the action is unavailable, verify that the environment has at least
two nodes.