Managing multiple servers efficiently

LinuxJournal Manage multiple servers efficiently


How can I manage apt efficiently on multiple machines?

Plan: Create pubkey-based auth with privkey protected by a decent password. Then can use ssh-agent and simultaneously upgrade multiple systems. Might even be able to script this down to one or two short commands.

Interesting snippet:

Here is the ~/.ssh/config file in my local account (the account I’m making SSH connections from):

Host dh-user1
User user1
IdentityFile ~/.ssh/dh-user1

Host dh-user2
User user2
IdentityFile ~/.ssh/dh-user2


Export PDF file containing comments using Acrobat Professional

I have Acrobat Professional for OS X. I semi-frequently use it to mark-up changes on a document where it’s too complicated to print and get a modified paper copy to the intended recipient. Using the markup tools is reasonably straightforward. Producing a PDF will drive a man insane. The reasonable thing to do (in my opinion, biased by the fact that Apple includes such nice native PDF support in the print dialogs) is to try to print a marked up version and then click the PDF button to save it as a PDF.

Well, Acrobat has apparently hooked this feature and says that such support is unavailable (don’t recall the exact message). It suggests using File -> Save instead. All exploration of Save, Save As, Export, etc lead nowhere. It’s particularly frustrating as some of the buttons on the print dialog box will actually let you see a preview of the document with all of its markup, connecting lines, etc. beautifully laid out.

To get that same box with a PDF option instead of a print option, one must instead select “Summarize Comments” from the “Comments” Menu. In addition to the various options for how comments should appear, there is a button to produce a PDF.

This is not intuitive! The normal place in an Apple system appears to be consciously disabled! The advice from that disabled screen is wrong! Adobe, step it up!

grub2 doesn’t allow passing arguments to ‘modules’ in multiboot environment

This seamingly reasonable entry will fail to boot (waiting for root filesystem, iirc):

menuentry “Xen 3.2″ {
multiboot (hd0,1)/xen-3.2-1-amd64.gz dom0_mem=256M
module (hd0,1)/vmlinuz-2.6.18-5-xen-amd64 root=/dev/sda2 ro
module (hd0,1)/initrd.img-2.6.18-5-xen-amd64

The issue is that the arguments “root=/dev/sda2 ro” do not actually get passed to the kernel. If you’re sufficiently patient and you get dropped to a busybox shell, ‘cat /proc/cmdline’ will demonstrate this. A possible work-around if you build your own kernels is to set the kernel command line options statically at compile time. It’s the very last option under “Processor Type and Features” or whatever (don’t recall exactly).

This strikes me as a pretty crippling limitation of grub2. I hope I’m just missing something that will be obvious in hindsight.

Two Google Voice accounts forwarding to one mobile phone

This post enabled me to figure out that Google Voice doesn’t insist that a number be “reclaimed” if one tries to associated it with more than one Google Voice account. The actual restriction is on SMS handling. In my particular case, I just want the phone to ring. The trick is to register the mobile phone as a Home or Work phone with both Google Voice accounts. If no SMS message support is involved, then Google Voice won’t insist on “reclaiming” the number.