An ArcGIS Server site comprises one or more ArcGIS Server machines that have the ArcGIS Server component installed. 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.
When you have installed and configured ArcGIS Server on a new machine, you can use the Join Site operation to add it to an existing site when you sign in to ArcGIS Server Manager. You can also add ArcGIS Server machines to your site using ArcGIS Server Manager or the join-site command line utility.
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 the same version number as the other ArcGIS Server machines in the site.
- It must have the same license as the other ArcGIS Server machines in the site.
- It must be able to read and write to the site's configuration store and server directories.
- 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.
- 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.
Recommendations for joining a machine to a multiple-machine site
If you are creating a multiple-machine site, the new machine must be running on the same operating system platform as the other ArcGIS Server machines in the 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 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.
Configure the server directories and configuration store to use shared paths
An ArcGIS Server site with multiple machines must share the folders containing the site's server directories and configuration store. Ensure that the ArcGIS Server account has permissions to read and write to the shared folder. On Windows, these permissions must be set on both the Sharing and Security tabs of the folder properties dialog box.
Although it is possible to share existing drive-letter-based locations for the configuration store and server directories, it is recommended that you move these locations to a fault-tolerant file server. This is especially important in cloud deployments, where automatic scaling mechanisms might add and remove machines from your site without awareness of which holds the configuration store.
ArcGIS Server does not support shared network directories that are hidden or use special characters (such as $).
Once you share the server directories and configuration store, you need to configure the site to use the new, shared paths. You can do this in ArcGIS Server Manager by following the instructions below. Note that your server will experience a period of downtime while these steps are executing.
Edit the server directory and configuration store paths in ArcGIS Server Manager
To edit the server directory and configuration store paths in ArcGIS Server Manager, follow these steps.
- Open ArcGIS Server Manager for the ArcGIS Server site and log in. If you need help with this step, see Log in to Manager.
- Click Site > Server Configuration > Configuration Store to edit the configuration store path. Provide the shared path of the configuration store location. The contents of the configuration store are moved to the new location and all services are restarted.
- Click Site > Server Configuration > Directories to edit the server directory paths. For each directory, click its Edit button and provide the new shared path for the directory. When you edit a directory path, the contents of the directory are copied to the new location unless you are editing a cache directory. When you edit a cache directory location, you must copy the cache to the new location manually.