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Apple OS X Server: Caching and Software Update services

Find out how to enable the Caching and Software Update services on your OS X Server.



The saying that something is only as strong as its weakest link lends itself to many different circumstances. In fact, it can be applied to modern day computing with respect to system and application updates across various platforms.

Specifically, this article focuses on two services that address patch remediation in similar ways but implement it distinctly -- and each has its own caveats. One offers a simplified “set it and forget it” method that can be used for wired and mobile devices alike, and the other offers a more targeted approach that's aimed toward IT administrators and allows for a degree of control as to what's available for download. Let's take a closer look at these two options.

I.  Caching service

Here are the requirements for using the Caching service:

  • Mac computer running OS X Server 10.7+
  • Minimum 25 GB available hard drive space to store updates
  • Wired ethernet connection (preferred)
  • Broadband connection to download updates

Follow these steps to enable Caching:

  1. Open and authenticate using admin-level credentials when prompted to do so
  2. Select Caching from the Services pane (Figure A), and then click the Edit… button next to Volume to select the hard drive that the software packages will be saved to
    Figure A
  3. Click Use Selected Volume to write the changes (Figure B)
    Figure B
  4. Use the slide to adjust the cache size or the maximum amount of hard drive space allotted to host the downloaded content (Figure C)
    Figure C
  5. Turn the service to ON

That’s it! With the Caching service enabled and configured, any updates or purchases from the App Store will be cached for future use on the local server. Subsequent download requests for content that has already been cached will first look to the cache server for a copy of the application/update. If found, it will download it directly from the local server, containing traffic to the LAN; If the desired content has not been cached yet, it will download it from the Internet as it normally does, and a copy will be stored by the caching service.

II.  Software Update service

Here are the requirements for using the Software Update service:

  • Mac computer running OS X Server 10.7+
  • DNS registration
  • Wired ethernet connection (required)
  • Broadband connection to download updates
  • Proxy servers are not supported (recommended by Apple that they're disabled)
  • Open necessary server addresses and ports to access update repositories 

Follow these steps to enable the Software Update service:

  1. Open and authenticate using admin-level credentials when prompted to do so
  2. Select Software Update from the Services pane (Figure D)
    Figure D
  3. Click on the Automatic or Manual radio button to determine whether you wish for the service to download all updates automatically or if you wish to enable fine-grained tuning to allow only specific updates to become available to end-users (you may wish to consult any IT policies the organization may have in place to be in compliance)
  4. Turn ON the Software Update service, and click the Updates tab (Figure E)
    Figure E
  5. Click the cogwheel button and select Check for Updates… from the drop-down menu (Figure F)
    Figure F
  6. Depending on your Internet connection, it may take some time to correlate a list from Apple’s update servers and present a listing of the updates available for authorization. The updates can be downloaded and enabled individually or selected at random by holding down the command key. (Figures G and H)
    Figure G
    Figure H
  7. Once the selection(s) have been made, the service will download the update and store it on the local server for updating in the future by devices on the LAN.*

*Note: Software Update services is only half of the equation. In order for devices to detect and download updates from your local server, they must be configured to do so. This will redirect requests from Apple’s update servers to your own, locally hosted OS X server. Luckily, this can be accomplished rather painlessly using either Profile Manager (which is part of OS X Server), manually via the Terminal, or using some form of management console, such as Apple Remote Desktop. Please refer to Apple’s KB article for the specific steps and commands necessary to reconfigure your devices to communicate with locally hosted Software Update services. 

Caching or Software Update services? Pros vs. cons

  • Caching stores both software updates and App Store purchases; Software Update stores only updates.
  • No additional configuration is required to use the Caching service, which is great for mobile devices like iPhones/iPads; Computers using Software Update must be configured to connect to the local server manually before downloading updates can proceed.
  • Caching is based on device requests for data. If a client does not request the latest version of iTunes, for example, it will not be cached automatically; Software Update downloads all updates from Apple’s servers and stores them for later use automatically (default).
  • Software Update allows IT departments more control over what's allowed to be installed/updated by pre-authorizing updates for end users; Caching does not allow such control and will store any update or app an end user downloads -- whether they're allowed by IT or not.

As each organization does business a little differently, the needs of its end users differ as well. Good thing for us all, Apple has provided multiple approaches to tackling updates. Unfortunately, Caching and Software Updates cannot be used together. Both services can be setup and configured for use, but Caching will not read the updates stored by Software Update and vice-versa. So, take precaution if deciding to utilize both, because the updates may be downloaded and stored several times over, eating up precious storage capacity.

Both services are flexible enough to co-exist, and they provide strengths to the other's shortcomings, which will benefit end-users and IT personnel. Furthermore, with the growth of BYOD and the proliferation of Apple tablets and smartphones, Caching may very well be a great way to provide updates to end-user mobile devices without being intrusive. Software Updates, on the other hand, can be used on company desktops and laptops to ensure they always have exactly the updates necessary to keep mission-critical devices productive. Ultimately, both services will minimize on the bandwidth utilization, so resources shouldn’t be too tapped out -- and everyone wins.



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