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Configure a multiple-machine ArcGIS Server site

ArcGIS Server has a scalable architecture that allows deployment sizes ranging from one to many machines. Service requests for maps, address coordinates, geoprocessing jobs, and so on, are each assigned to an available machine in the site. That machine then draws the map, finds the address coordinate, or runs the geoprocessing tool, and returns the result to the client.

Adding a new machine to an existing ArcGIS Server site can be done temporarily to migrate to new machines or more permanently to increase the resources and processing power of the server site. Sites with two or more machines can also be configured for high availability to protect against downtime and data loss in the event of computer failure.

All machines in an ArcGIS Server site have the ArcGIS Server component installed. After you install ArcGIS Server on the first machine, you'll need to create the site. When you install and configure ArcGIS Server on a new machine, you can use the Join Site operation to add it to this existing site. You can also add ArcGIS Server machines to your site using ArcGIS Server Manager or the join-site command line utility.

Configuration store and server directories

When you create a site, you determine where to store the critical files and configuration information for your site. This directory is called the configuration store. Your site also has server directories that store service output files, geoprocessing jobs information, service definitions, cache tiles, and other items. When you add a machine to the site, it is configured to point to the configuration store and server directories.

In on-premises deployments, you might choose to put the configuration store on a machine or disk that is not dependent on the ArcGIS Server, such as a fault-tolerant file server. This allows you to add or remove machines from the site without worrying about which of them has the configuration store installed.

Cloud deployments offer the option of storing the configuration store and server directories in a cloud service, including:

These storage locations and availability are managed by the cloud provider. Visit the documentation for each respective cloud provider for more information.

Criteria to add an ArcGIS Server machine to a site

Below are the criteria that need to be met for you to be able to add an ArcGIS Server machine to a site.

Requirements for joining a machine

If you are using the Join Site operation to migrate a machine, the new and existing machines do not need to match; however, if you intend to keep all machines in the site permanently, ensure that the new machine meets the following criteria:

  • It must be running on the same operating system platform as the other ArcGIS Server machines in the site.

  • It must use the same version of ArcGIS Server as the other ArcGIS Server machines in the site.

  • It must have the same license as the other ArcGIS Server machines in the site.

    Note:

    This includes perpetual and term licensing, which are not compatible.

  • It must be able to read and write to the site's configuration store and server directories.

  • It must be able to communicate with the other ArcGIS Server machines in the site through the ports listed in Ports used by ArcGIS Server. This may require adjustment of firewall settings.

  • It must be able to read any data referenced by services on the site. A good way to verify this is to confirm that the machine has permissions to all the data storage locations registered with the site. See Data sources for ArcGIS Server to learn more about these registered locations.

  • All running ArcGIS Server machines must be able to read and write to the same shared directories through NFS using the same mount point on all systems. For example, if you are mounting a file server shared directory to /arcgis on one machine and using it for your configuration store and server directories, all machines must also mount that same directory to /arcgis.

  • All ArcGIS Server machines must be running under users who have the same user ID (uid) or group ID (gid) to read and write to the shared configuration store and server directory locations.

  • It must be running ArcGIS Server under the same ArcGIS Server account as the other ArcGIS Server machines in the site. This can be a domain account, or it can be a local account with a name and password that are identical on all machines. See The ArcGIS Server account to learn more about this account.

  • Each machine's clock must be synchronized to a common time source to ensure consistent time across the site.

Recommendations for joining a machine to a multiple-machine site

If you are creating a multiple-machine site, it is recommended that you use the same operating system version and hardware resources for all machines in the site.

For example, if your site is composed of ArcGIS Server machines, each running on Red Hat Enterprise Linux Server 8 with a 3 GHz processor and 8 GB of RAM, the machine you add to the site should also have the same operating system and hardware specifications.

For example, if your site is composed of ArcGIS Server machines, each running on Microsoft Windows Server 2016 with a 3 GHz processor and 8 GB of RAM, the machine you add to the site should also have the same operating system and hardware specifications.