High Sierra sees the Caching service moved out of macOS Server and into the client macOS. This means administrators no longer need to run the Server app on caching servers. Given the fact that the Caching service only stores volatile data easily recreated by caching updates again, there’s no need to back the service up, and it doesn’t interact with users or groups, so it’s easily divested from the rest of the Server services.
And the setup of the Caching service has never been easier. To do so, first open System Preferences and click on the Sharing System Preferences pane. 
From here, click on the checkbox for Content Caching to start the service.
At the Content Caching panel, the service will say “Content Caching: On” once it’s running. Here, you can disable the “Cache iCloud content” option, which will disable the caching of user data supplied for iCloud (everything in here is encrypted, by the way). You can also choose to share the Internet Connection, which will create a wireless network that iOS devices can join to pull content. 
Click Options. Here, you can see how much storage is being used and limit the amount used.
defaults read /Library/Preferences/com.apple.AssetCache.plist
Which returns the following configurable options:
Activated = 1;
CacheLimit = 0;
DataPath = “/Library/Application Support/Apple/AssetCache/Data”;
LastConfigData = <BIGLONGCRAZYSTRING>;
LastConfigURL = “http://suconfig.apple.com/resource/registration/v1/config.plist”;
LastPort = 56452;
LastRegOrFlush = “2017-09-11 16:32:56 +0000”;
LocalSubnetsOnly = 1;
PeerLocalSubnetsOnly = 1;
Port = 0;
Region = 263755EFEF1C5DA178E82754D20D47B6;
ReservedVolumeSpace = 2000000000;
SavedCacheDetails = {
SavedCacheSize = 0;
ServerGUID = “EB531594-B51E-4F6A-80B9-35081B924629”;
Version = 1;}
This means that all those settings that you used to see in the GUI are still there, you just access them via the command line, by sending defaults commands. For example,
defaults write /Library/Preferences/com.apple.AssetCache.plist CacheLimit -int 20000000000
You can
AssetCacheManagerUtil status
Which returns something similar to the following:
2017-09-11 11:49:37.427 AssetCacheManagerUtil[23957:564981] Built-in caching server status: {
Activated = 1;
Active = 1;
CacheDetails = {
iCloud = 4958643;
“iOS Software” = 936182434;};
CacheFree = 472585174016;
CacheLimit = 0;
CacheStatus = OK;
CacheUsed = 941141077;
Parents = ();
Peers = ();
PersonalCacheFree = 472585174016;
PersonalCacheLimit = 0;
PersonalCacheUsed = 4958643;
Port = 56452;
PrivateAddresses = (“192.168.104.196”);
PublicAddress = “38.126.164.226”;
RegistrationStatus = 1;
RestrictedMedia = 0;
ServerGUID = “EB531594-B51E-4F6A-80B9-35081B924629”;
StartupStatus = OK;
TotalBytesDropped = 0;
TotalBytesImported = 4958643;
TotalBytesReturnedToChildren = 0;
TotalBytesReturnedToClients = 166627405;
TotalBytesReturnedToPeers = 0;
TotalBytesStoredFromOrigin = 166627405;
TotalBytesStoredFromParents = 0;
TotalBytesStoredFromPeers = 0;
You can also use AssetCacheManagerUtil to manage tasks previously built into the Server app. To see the available options, simply run the command:
bash-3.2# /usr/bin/AssetCacheManagerUtil
Which would show the following:
Options are:
-a|–all show all events
-j|–json print results in JSON
-l|–linger don’t exit
2017-09-11 11:57:30.066 AssetCacheManagerUtil[24213:569932] Commands are:
activate
deactivate
isActivated
canActivate
flushCache
flushPersonalCache
flushSharedCache
status
settings
reloadSettings
moveCacheTo path
absorbCacheFrom path read-only|and-destroy
As such, to enable the server:
bash-3.2# /usr/bin/AssetCacheManagerUtil activate
To disable the server
bash-3.2# /usr/bin/AssetCacheManagerUtil deactivate
To check if the server can be activated
bash-3.2# /usr/bin/AssetCacheManagerUtil canActivate
To flush the cache of assets on the server:
bash-3.2# /usr/bin/AssetCacheManagerUtil flushCache
To reload settings if you make any changes:
bash-3.2# /usr/bin/AssetCacheManagerUtil reloadSettings
To move the database
/usr/bin/AssetCacheManagerUtil moveCacheTo "/Volumes/SONY/Library/Application Support/Apple/AssetCache/Data"
Finally, if you’d like to see the caching server your client system is using, you can run the following command:
/usr/bin/AssetCacheLocatorUtil 2>&1 | grep guid | awk '{print$4}' | sed 's/^\(.*\):.*$/\1/' | uniq
And if you use Jamf Pro and would like to use this as an extension attribute, that’s posted here: https://github.com/krypted/cachecheck. I didn’t do any of the if/then there, as I’d usually just do that on the JSS.
Note: To see how AssetCache interacts with Tetherator, see Tethered Caching of iOS Assets from macOS 10.12.4.
