In a previous post I’ve described a method for configuring Active Directory Authentication for SAS® on Linux (with realmd). One of the packages that’s installed is oddjob-mkhomedir. This package normally handles any requirement for auto-creating home directories for those AD users on Linux. Unfortunately it doesn’t seem to get used by the SAS Object Spawner. I ran into this issue again today when logging into SAS Studio 4.2 as an AD user on the SAS Viya™ 3.2 platform. I wasn’t able to login because the AD user’s Linux home directory didn’t exist and hadn’t been auto created. After manually creating the home directory the login succeeded. I would rather get auto-creation working so I wouldn’t need to manually create home directories for each SAS user that was likely to use SAS Studio. Thankfully I was able to find a solution that I’ll describe in this post. Continue reading “Auto Creation of Linux Home Directories for SAS Users”
This is another post in the series about configuring a SAS platform on Linux to use Integrated Windows Authentication (IWA), in this post I’m going to jot down some notes on steps 1-7 – configuring the Linux server for Active Directory (AD) Authentication.
Some time has passed since I wrote the original post, and a few things have changed. I’m now running SAS 9.4 M3, but this post should equally apply to SAS 9.4 M2. I have also switched the Linux distribution from Debian to CentOS 7.1. I am also using a much simpler method of joining the Linux server to the AD domain, using the realmd package (previously there were lots of individual steps using the underlying packages but realmd automates most of this). In this post I’m going to outline the simpler method using realmd of course.
SAS® 9.4 M3 is now available (as discussed by Andy Ratcliffe in his recent NOTE: blog post), so I’m downloading a new SAS depot using the SAS Download Manager. I’m downloading it onto a Linux server that happens to have X11 available, but I’m choosing to use console (text) mode, rather than the default X11 windowed mode.
Using SAS Download Manager in console mode is my preferred method because I find it more flexible. Why Console mode? I know from experience that a SAS depot download is going to take a few hours and, if I run SAS Download Manager in windowed mode, I risk losing the remote X connection if there are any network disruptions between me and the server. By running SAS Download Manager in console mode, in combination with screen over an SSH session, I can easily disconnect/reconnect as required. I can disconnect (Control-A D) when I leave the office to go home, and reconnect (screen -r) when I get home to check on progress. I can also get screen to capture a log of the session in a text file (screen -L).
Of course, I could have used a Windows or Mac version of the SAS Download Manager to download onto a laptop and then upload onto the server, but that ties the laptop to a single location for the duration of the download. Plus if I’m not near the server at the time, I’d have to download and then upload nearly 50GB of SAS depot. If I’m traveling with my 4G mobile broadband connection, the server also has a much faster and much cheaper internet connection than I do! These are some of the reasons I prefer console mode.
To run SAS Download Manager in console mode Continue reading “SAS Download Manager in Console Mode”
Continuing on the theme of configuring a SAS 9.4 M2 platform on Linux to use Integrated Windows Authentication (IWA), in this post I’m going to jot down some notes on steps 12-15 – configuring the SAS mid-tier on a Linux server for IWA with fallback to form-based authentication (when IWA is not available). This includes delegation, so that IWA users of mid-tier apps like SAS Studio are able to get IWA access to a SAS Workspace Server (and avoid having to store their passwords in metadata or switch to using SAS Token Authentication).
If you’re wondering what happened to steps 1-11, I’ll try get to those earlier steps in future posts. I’m starting at step 12 because someone recently asked me a question about configuring an IWA mid-tier and so it seemed like a good idea to get this blog post done first. Of course, when actual implementing, it’s always good to start at the beginning, building up the foundations, and verifying those first steps are working well before moving on to the next steps. So these steps assume you already have a working implementation where SAS desktop applications (like SAS Management Console & SAS Enterprise Guide) are able to connect to the SAS metadata server using IWA, and also to get IWA access to an appropriately configured SAS Workspace Server.
I have found the best mid-tier related documentation resources for this type of configuration are these ones:
- SAS Global Forum Paper SAS102-2014: An Advanced Fallback Authentication Framework for SAS® 9.4 and SAS® Visual Analytics by Zhiyong Li & Mike Roda (SAS Institute)
- The Support for Integrated Windows Authentication section in the SAS 9.4 Intelligence Platform: Middle-Tier Administration Guide, Second Edition
- The Web Authentication section in the SAS 9.4 Intelligence Platform: Middle-Tier Administration Guide, Second Edition
… and there are a few others listed in a previous blog post.
One of the reasons I’m writing this post is to get down some notes on a config that worked for me. The documents referenced above cover a variety of scenarios including plain basic web authentication with an XML file-based UserDatabaseRealm, an LDAP JNDIRealm, IWA (SPNEGO) without fallback, as well as fallback to form-based SAS authentication. Getting the right mix of settings, that didn’t conflict with each other, took me a long time to determine (my mid-tier takes about 20 minutes to restart whenever I want to test a modified config). Along the way I encountered pop-up basic web authentication dialogs when IWA should have worked, and infinite browser-refresh loops for the SAS Logon Manager when IWA was disabled in the browser and I was expecting fallback to SAS authentication. This post is about the final config that worked for me. I know I’ll be referring to this post again, and I hope it proves helpful to others too.
Yesterday I wrote a post about configuring a SAS® 9.4 M2 installation on Linux for Integrated Windows Authentication (IWA) with mid-tier fallback form-based authentication to handle situations where IWA was not available or was disabled. I also repeated this configuration with a SAS Visual Analytics 7.1 installation (based on SAS 9.4 M2). This means that domain users within an organisation, who can participate in IWA, can simply open a browser, navigate to SAS Visual Analytics, and be logged in automatically using their Windows login. Other users without a domain account, on a machine that is not in the domain, or who have deliberately disabled IWA in their browser, will see the familiar SAS Logon Manager login form where they can manually provide a user id and password.
One of the other reasons I built this configuration was to find out what happened with SAS Visual Analytics Guest Access in an IWA fallback configuration like this. Essentially, I wanted to find out if I could get maximum flexibility by supporting IWA users, form-based authentication users, and guest/anonymous access all at the same time.
One of the reasons I wanted to test this was a reference I remembered seeing in the SAS documentation. The Web Authentication section of the SAS 9.4 Intelligence Platform: Security Administration Guide, Second Edition, lists one of the limits of Web Authentication as “Not compatible with anonymous access”. This is also repeated in the PUBLIC Access and Anonymous Access section too.
It makes sense that anonymous access is not compatible with web authentication in a standard non-fallback configuration. If authentication is automatic and it fails then access is denied. An IWA fallback configuration is slightly different though – you have a choice whether to do web authentication or SAS authentication (e.g. IWA or non-IWA). If you choose SAS authentication then perhaps anonymous access might still be available as an option. I decided to test it out.
I ran 4 test scenarios to see how they were handled in an IWA with fallback configuration:
Continue reading “SAS Visual Analytics Guest Access with IWA Fallback”