Enabling High Availability

High availability (HA) allows you host two or more separate instances and having them read data from a shared location, such as a network share or drive.

High availability on SquaredUp DS works by mirroring the files on the share back onto the local disk.

This style of deployment is typically used to:

  • Enable load balancing between servers hosting the same content
  • Create two or more different access points into SquaredUp DS with different modes of authentication (e.g. one instance with Windows authentication and the other with forms)

Distributed file system (DFS) shares are supported, under the proviso that DFSR (replication) is either disabled, or works in a limited capacity on SquaredUp DS files. For example, performing replication only at specific times or manually when SquaredUp DS is not running. If DFSR is used then the Primary and Secondary servers will not see the same information.

You may also like to watch this training webinar about 'SquaredUp DS v4 High availability' (25 mins):

Requirements

  • Two or more separate servers for installing SquaredUp DS v4 or above. For high availability to work, every SquaredUp server must be running exactly the same version.
  • A shared network folder or drive
  • A SquaredUp DS license with a Secondary activation key

A Teams edition license (or above) is required for this feature.

To upgrade please contact [email protected].

To check the license edition you are using see How to check which license key is being used. To see what is included in different product edition licenses see the Licensing Overview.

Understanding Primary and Secondary servers

Decide which server will be your Primary SquaredUp server and which will be your Secondary server(s):

  • A high availability setup must consist of at least one Primary server. Without a Primary server, the servers licensed as Secondary will operate with reduced functionality and named users.
  • The Primary server will use the Primary license key, and any existing dashboards on this server will become the dashboards on the share, to be used by all servers.
  • The Secondary server(s) will use the Secondary license key, the dashboards on these servers will be ignored and the content of the Primary server will take precedence. You can have one or more Secondary servers.

If a Secondary server is out of contact with the Primary server you will see a notification in the notifications area from the right-hand menu > notifications.

  • Within 2-3 hours of the Primary server being unavailable for any reason you will receive a notification.
  • After 3 days of no contact with the Primary server a critical notification is shown warning that shut down is imminent.
  • After 5 days of no contact with the Primary server the Secondary server will no longer be available, effectively 'shut down'.
  • After the 5 days you can recycle the Secondary server's SquaredUp application pool to restore limited access.
  • Recycling the Secondary server's application pool, or rebooting it, at any point when the Primary is offline means that the Secondary server will drop down to limited access.

Limited access will allow only 5 named users and features such as Open Access, VADA, Web API and Visio tiles will not be available.

Configure permissions on the share

Before configuring HA it is important to check the permissions on the share itself. The share has its own permissions which cannot be viewed via Windows Explorer, and they always take precedence over the file and folder permissions. If the SquaredUp DS application pool identity (How to check and modify the application pool identity) is not allowed to read and change, then the permissions added to the folders by the SquaredUp command are overridden/ignored by the share, and SquaredUp DS will fail to start with an 'Access denied' error.

In Computer Management check that the SquaredUp DS application pool account has 'Read' and 'Change' permissions to the share itself, as described below:

  1. On the machine that hosts the share, click on the Start button > type Computer Management > open Computer Management.
  2. Navigate to System Tools > Shared Folders > Shares.
  3. Right-click on the SquaredUp share and then on Properties.
  4. On the Share Permissions tab, check that all SquaredUp DS application pool accounts have read and change permissions:
  5. If your servers are using a domain service account as the SquaredUp DS application pool identity (How to check and modify the application pool identity) then this account should be given read and change permissions.
    If your SquaredUp servers are using Network Service as the SquaredUp DS application pool account (How to check and modify the application pool identity), then all the machine accounts for the SquaredUp Primary and Secondary servers should be given permissions, for example, Squpserver01$ and Squpserver02$.
    It should not be necessary to grant full control, and this could pose a security risk.

Configuring each server for high availability

The first server that you configure for HA, will be the one from which dashboards and profiles are copied to the HA share. Follow the steps below for each server, one at a time:

  1. Install and activate SquaredUp DS using the appropriate Primary or Secondary activation key (see How to install SquaredUp DS for SCOM and How to activate your license).
  2. On the server open a command prompt as an administrator (from Start > type cmd, right-click on the Command Prompt icon and click Run as administrator).
  3. Change to the SquaredUp DS installation location, for example type:
    cd C:\inetpub\wwwroot\SquaredUp
  4. Identify whether the SquaredUp DS application pool identity is running as a domain service account or as NetworkService (How to check and modify the application pool identity) and run the SquaredUp command with ha:
    If the SquaredUp DS application pool identity is a domain service account use this account in the command:

    squaredup ha --path=<network share path> --user=domain\user

    where domain\user is the SquaredUp DS application pool identity. First check what the SquaredUp DS application pool account is for each server is using (How to check and modify the application pool identity). In a load balanced environment using Windows authentication (Kerberos), both servers must be using the same application pool identity. (In environments not using Kerberos, it is possible for the servers to use different application pool identities). This allows the tool to give the specified SquaredUp DS application pool account read and write permissions to the folder and files on the share.
    and where <network share path> should be replaced by a drive or path specification for your network share. The folder/share must already exist: SquaredUp DS cannot create it automatically (for example, specifying \\myhost\folder is invalid if folder is not already shared by myhost). The path should not contain a filename (i.e. it should be \myshare etc. and not \myshare\squaredup.index).
    For example:
    If your SquaredUp DS application pool identity is NetworkService you should use the SquaredUp server name followed by the $ dollar symbol as the username when you run the command on that server.

    squaredup ha --path=<network share path> --user=domain\SquaredUpServer$
    where SquaredUpServer$ is the SquaredUp server name followed by $, for example, Squpserver01$.
    Remember, that the first server that you run this command on will be the one from which dashboards and profiles are copied to the HA share. Later, after checking the Primary server is configured correctly you will run this command on all your other SquaredUp servers to configure each of them to use HA AND to give them permissions to the HA share.
    • X:\
    • \\myhost\folder (UNC path)
  5. Navigate to SquaredUp DS using a web browser either on the server itself, or from a client machine. (Note: The previous command will have automatically recycled SquaredUp DS, so you will need to login again).
  6. After logging in, the server should behave identically to how it did post-installation. There are several ways to confirm that HA is in effect:
    For the Primary server:
    [WRN] Shared cryptography is enabled: behaving as a PRIMARY server
    For a Secondary server:
    [WRN] Shared cryptography is enabled: behaving as a SECONDARY server
    • The path to which HA has been pointed (e.g. \\myhost\folder) should contain a file called squaredup_scom_[version].index (or squaredup_[version].index if HA was configured on v5.0 or below).
  • The SquaredUp DS log (\SquaredUp\transient\log\rolling.log See Where to find log files) should contain the following text:
  1. Once the Primary is confirmed to be running in HA mode, the Secondary server(s) can be configured using the Secondary license key. Repeat the above steps for the Secondary servers. Content already present on these servers will be ignored and not displayed. Instead, each Secondary server will now behave as an exact mirror of the Primary server.
  2. After configuring HA, log in to the Secondary server(s) and check the configuration:
    • The licensing details for the Secondary in the right-hand menu ☰ > system > named users should reflect the overall quantity of users that your license was purchased for
    • The Secondary should now be displaying the same dashboards and content as the Primary.
    • Newly created content on Primary or Secondary should be visible to both nodes.

Upgrading SquaredUp DS when using high availability

For high availability to work, every SquaredUp server must be running exactly the same version.

Upgrading SquaredUp DS v4 and above in a high availability setup no longer requires all servers go offline for upgrade. Instead, each server can now be upgraded one at a time, and the other servers will continue to serve dashboards.

However, once upgrade of at least one server is performed, changes made to dashboards by servers running the old version of SquaredUp DS are ignored, and will be lost when those servers are eventually upgraded (that is to say, the dashboards and content in the upgraded servers becomes authoritative over dashboards and content from the older un-upgraded servers).

  • 10 minutes after upgrade of a server is performed, the servers yet-to-be-upgraded will automatically enter a read-only state, to prevent new dashboards being created or edited. This is visible in SquaredUp DS as a yellow banner at the top of the page.
  • Dashboards (or other content) created or edited on an un-upgraded server before the server automatically goes read-only, will be permanently lost once the server is upgraded to the newer version. For this reason, we recommend advising users to not make changes once you start your upgrade process.

Consider initiating your upgrades out-of-hours - even if you don't finish them on all servers. This way, all of the servers yet to be upgraded will have entered read-only mode automatically by the time users come to view or edit their content.

SquaredUp DS v4.5 fixes the issue of the named user list not being synchronised across HA servers. When upgrading to v4.5 the first server that you upgrade will be the one from which the named user list is copied to the HA share and that list becomes the authoritative version. The named user list from subsequently upgraded servers will be lost, as the single authoritative named user list is synchronised across HA servers.

Follow the steps below to upgrade each server:

  1. Prepare to take the server you are upgrading offline. For example, notify users, disable the load balancer allocation for it, put it in maintenance mode etc.
  2. Download the latest version of SquaredUp DS, run the installer and upgrade the server.

    Get the latest version of SquaredUp DS for SCOM

  3. Log on to the SquaredUp DS on the server once upgraded.
  4. Upgrade any other SquaredUp servers.

Disabling high availability

You may wish to switch high availability off for one or more servers, for example if one of the servers is going to be unavailable for a long period of time. Remember, for SquaredUp DS to work with your full license allocation, you need to ensure that there is still a Primary licensed server available.

SquaredUp DS mirrors the content of the share location back to the local disk: So that each member of a high availability set is an approximate replica, even when disconnected from the share. This means that HA can safely be disabled at any time, and once disabled the content of SquaredUp DS will reflect the network share data at the point just before the link was broken.

  1. On the SquaredUp server open a command prompt as an administrator (from Start > type cmd, right-click on the Command Prompt icon and click Run as administrator).
  2. Change to the SquaredUp DS installation location, for example type:

    cd C:\inetpub\wwwroot\squaredup
  3. Run the SquaredUp command with ha to disable HA:

    squaredup ha --disable

You will also need to reconfigure the load balancer allocation to take into account the server(s) no longer available.

Moving the HA share

To move the HA share, the initial setup steps can simply be repeated as below, just specifying a new share path. This is because each server maintains a local disk copy of the share content - and the first server to startup after being pointed at the new share will build the share’s content from its own.

  1. Create the new share and follow the steps to Configure permissions on the share.
  2. On any SquaredUp server run the steps to Configuring each server for high availability using the path of the new share.
  3. Browse to SquaredUp DS in a web browser and log in. This will restart SquaredUp DS as the previous command will have automatically recycled the SquaredUp DS application pool. The files will be copied to the share from the first SquaredUp DS instance to start up. It should not matter which SquaredUp DS instance this is, as they should all be in sync, having been using HA previously. If you need to specify form which SquaredUp DS instance the files are copied to the new share, you should take care to open this SquaredUp DS instance by browsing to it directly, for example
    https://SquaredUpServer1/SquaredUp

  4. Run the steps to Configuring each server for high availability on all the other servers using the path of the new share. This will point all the servers to the new share and the files that were copied there in the previous step.

Backup SquaredUp DS on each server as normal (How to backup and restore SquaredUp DS for SCOM). No additional actions are required: Any SquaredUp server can rebuild the content of the network share from its local disk data. So backing up individual SquaredUp DS instances (and not the network share) is sufficient.

If the share does have to be recreated, ensure you configure permissions on the share first:

To restore the files to a new or empty HA share run the HA configuration steps from any SquaredUp server, to copy the files from this server to the share. See Enabling High Availability

To restore to an existing share folder you must delete the file SquaredUp_scom_[version].index, if it exists, in order for the restore to proceed. Restoring will then recreate the SquaredUp_scom_[version].index file on the share. (This file will be called SquaredUp_[version].index if HA was configured on v5.0 or below).

FAQs

Can I configure each server to use a different SCOM server, Data Warehouse or Open Access loopback URL?

Yes, see How to set up per-server configuration when using high availability (HA).

Troubleshooting

Only a few users can login an several features are unavailable

Only 5 users can login and several features such as Open Access, VADA, Web API and Visio tiles are unavailable

Check that HA mode is enabled, and that the Primary server is available.

Recycling the Secondary server's application pool, or rebooting it, at any point when the Primary is offline means that the Secondary server will drop down to limited access.

Limited access will allow only 5 named users and features such as Open Access, VADA, Web API and Visio tiles will not be available.

For more details see Understanding Primary and Secondary servers.

SquaredUp DS is displaying a message that it is in read-only mode

A SquaredUp DS instance will go into read-only mode if it notices that it is running an older version to another server.

Read-only mode will end once the server is upgraded to the same version.

My providers, PowerShell profiles, and PowerShell Run As accounts are out of sync across HA servers

In a High Availability environment, it can happen that the following items are not properly synced across servers:

Solution:

On your primary server, make an edit to any of your providers, PowerShell profiles, or Run As accounts.

Editing one provider will trigger a sync between all your providers across all your servers. Editing one PowerShell profile will sync all your PowerShell profiles, and editing one Run As account will sync all your Run As accounts.

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