UK Linux User Groups

This may be useful, may become useful, or may not:

• https://github.com/skx/sysadmin-util

As some readers might know, I work from home, and have worked from home for about 12 years. However I’ve never had a proper dedicated office, just a corner of a second bedroom or a bit of space on a sofa. That’s about to change.

Tomorrow, work starts on constructing a real office in my garden.

Work already started (for me) about a month ago, when I took down a shed and jack-hammered a patio to bits:

Shifting the whole lot into two skips:

Resulting in this empty, mostly flat space (about 20′ wide and 16′ deep, damn you council for chopping that tree down at the back …):

To be continued …

New in libguestfs ≥ 1.21.30 is the ability to use guestfish and some of the virt tools with remote disks.

Currently you can use remote disks over NBD, GlusterFS, Ceph, Sheepdog and (recently upstream) SSH.

For this example I’ll use SSH because it needs no setup, although this requires absolutely the latest qemu and libguestfs (both from git).

Since we don’t have libvirt support for ssh yet, so this only works with the direct backend:

$ export LIBGUESTFS_BACKEND=direct

I can use a ssh:// URI to add disks with guestfish, guestmount and most of the virt tools. For example:

$ virt-rescue -a ssh://localhost/tmp/f17x64.img [... lots of boot messages ...] Welcome to virt-rescue, the libguestfs rescue shell. Note: The contents of / are the rescue appliance. You have to mount the guest's partitions under /sysroot before you can examine them. ><rescue> mount /dev/vg_f17x64/lv_root /sysroot ><rescue> cat /sysroot/etc/redhat-release Fedora release 17 (Beefy Miracle)

Apart from being a tiny bit slower, it just works as if the disk was local:

$ virt-df -a ssh://localhost/tmp/f17x64.img Filesystem 1K-blocks Used Available Use% f17x64.img:/dev/sda1 487652 63738 398314 14% f17x64.img:/dev/vg_f17x64/lv_root 28316680 4285576 22586036 16% $ guestmount -a ssh://localhost/tmp/f17x64.img -i /tmp/mnt $ ls /tmp/mnt bin dev home lib64 media opt root sbin sys usr boot etc lib lost+found mnt proc run srv tmp var $ cat /tmp/mnt/etc/redhat-release Fedora release 17 (Beefy Miracle) $ guestunmount /tmp/mnt

Customer: "Hi, we have a printer that's off-line and I cant seem to get it back on. Also I have another printer I need adding to a PC."
Me: "OK but unfortunately you do not have a support contract with us so I'm afraid it's chargeable at £35 per hour."
Customer: "Yes I know we don't have a contract that's why we don't ring you very often."
Me: "Erm? OK?"
Customer: "Is there anyone there that can point us in the right direction?"
Me: "Yes, at £35 per hour."

Hello Mr Garage owner, you know you fitted a new wiper blade three years ago well I need some help with .........

53-55 Lichfield St
Wolverhampton
West Midlands
WV1 1EQ‎

Eat, Drink and talk Linux

Event Date and Time:  Wed, 17/04/2013 - 19:30 - 23:00

I've been getting into snorkelling a bit recently. I've always enjoyed it but recently I bought some good quality gear, replacing the toy shop crap I've been using. It's another world with good equipment! It's not easy to get time, but so far I've snorkelled Jervis Bay, Bushrangers Bay, Clovelly and The Haven in Terrigal.

My son has been asking what it's like, so I bought the Kogan waterproof camera case for $19. Took it out last weekend for a spin at The Haven but the visibility was terrible. The camera case works a treat though, and I'm looking forward to using it some more. Need to work out a strap to attach it to my arm or something though.

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In March I went off to the Photography Farm, an intensive three day residential workshop run by Lisa Devlin and her impressive creative team. Set on a massive farm, we were very well looked after, fed well and kept snug in the 16th century farmhouse. When I was looking at training and development activities I could do this year, the farm was the most popular suggestion and with good reason. It was a fantastic opportunity to meet other photographers, share ideas and talk into the small hours about power ballads.

The photos accompanying this post are from the farm’s styled shoot, an opportunity to photograph a couple in a way that there’s not always time to do on a wedding day. This shoot was inspired by the story of Jemima Puddleduck by Beatrix Potter, and featured a fantastic dress layered with feathers, some amazing eyelashes and a painstakingly detailed leafy bower. The models for the shoot were fellow photographer Hannah Millard and her husband Iwan, who both did a great job and got really into the shoot despite the cluster of photographers gathered around them. It’s interesting watching other photographers at work, the way they shoot and how they interact with their subjects: There’s always something to learn.

There were some very challenging sessions over the three days, but they were also the things I found most valuable. The farm was a great experience and I would thoroughly recommend it. Everyone was warm and friendly, the atmosphere relaxed, and the group size just right. I’m really rather jealous that there’s going to be another one in May!

Credits

Set Styling and Flowers by The Tea Set

Hair and Make Up by Elbie Van Eeden

Fashion Styling by Noir Creative

Dress by Oh My Honey

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The Debian Project Leader election has concluded and the winner is Lucas Nussbaum. Of a total of 988 developers, 390 developers voted using the Condorcet method.

More information about the result is available in the Debian Project Leader Elections 2013 page.

The new term for the project leader will start on April 17th and expire on April 17th 2014.

As previously mentioned I was looking to package pwsafe for Wheezy, as this is one of the few tools that I rely upon which isn't present.

There are now packages available, with the source on github.

I've also been doing some minor scripting because I've run into a few common problems recently:

run-parts

run-parts is a simple utility which will run every executable in a directory, more or less.

In Debian-land run-parts is the mechanism for /etc/cron.daily and /etc/cron.hourly - and that is where I've had problems recently.

Imagine you run a backup via cron.daily. Further imagine that you run a post-backup rsync and that this might take many many hours. If your backup takes >=24 hours you're screwed.

To that end I've patched my run-parts tool to alert and exit if a prior invocation is still running.

silent-run

I think everybody has this script - hide all output when running a command, unless the command fails. Looking today I see chronic from Joey's excellent moreutils does this. D'oh.

I think I've done more, but I cannot remember. In conclusion software is both easy and hard - easy because these two trivial changes were within my reach, but hard because years after encountering GNU/Linux we still have to add in the missing pieces.

Still could be worse, I spent four/five hours yesterday evening fighting with MS-SQL server, and that is time I'm never going to get back.

Start: 2013-04-13 11:00 End: 2013-04-13 17:00

We have regular sessions on the second Saturday of each month. Our meeting this month is at Sirius Corporation in Addlestone, Surrey. Thanks to Andrew Wilkins for hosting us this month.

New members are very welcome. We're not a cliquey bunch, so you won't feel out of place! Usually between 15 and 30 people come along.

I have finally reach the limit with unsolicited marketing calls (in spite of being registered with the TPS). So today I have implemented a couple of changes to the Asterisk phone system here.

1. All inbound calls with the number withheld will be presented with the number disconnected tones, then told that the call may be recorded (it will be!) before any phones ring.

2. If the call is from a telemarketer, I will transfer the call to sip:lenny@itslenny.com:5060

3. If they are already on my blacklist, they will automatically get transferred to sip:lenny@itslenny.com:5060

read more

Hi,

In the last 45 days, Vault.centos.org's 2 public facing machines delivered just under 66 TiB of data. So while we try and spread this load a bit ( its growing at 25 - 35% month on month ), we've had to make a few changes.

Firstly, isos are no longer directly downloadable from vault.centos.org, you will need to go the torrent route if you want older, deprecated release isos

Secondly, we've turned off multi range requests ( httpd will still accept upto 5 range's, and then block after that )

Over the next few days, we are going to recycle some of the larger disk mirror.centos.org nodes into vault.centos.org; If someone wants to contribute to this effort, please come find us on irc.freenode.net in channel #centos-devel or #centos-mirror or tweet us @centos or email us the address mentioned at http://wiki.centos.org/Donate - but keep in mind that need machines with more than 1 TiB of usable space, and more than 300mbps of network capacity, and since we will consume that bandwidth high density hosting facilities with high contention on the links wont work.

- KB

A couple of days ago, someone asked me whether the Gmail website was any good on mobile. I said: it seems so, the couple of times I’ve used it, but I’m not really sure. I’ll find out, I said.

You’d think I’d know better by now.

once more into the breach, dear enemies

The way to actually find out whether it’s any good, with the gmail web app as with all things, is to use it for real for a bit. So I decided that what I’d do is exclusively use the web app to read my mail on my phone for a week.

There are two base criteria here which must be met. First: I have to be able to get at gmail from an icon on my iPhone’s home screen, and second I have to get notifications when I get a new mail. Those two things are axioms, here: if they’re not possible, then my answer is “the gmail web app is crap” because I can’t use it. The easy bit first.

the easy bit

Go to gmail.com in the browser: press the share button, press “add to home screen”. Done.

notifications for a new email

Web apps have a notification API, but it’s not useful on mobiles, because the whole point of a new mail notification is that you get it even if you’re not looking at your mail app. You wouldn’t want to keep the gmail web page open all the time, even if you were allowed to do so on a phone, which you are not. (The Nokia N9 allowed this. No-one else does; mobile platforms routinely decide to quietly kill your app and then raise it from the dead again when you want it back, and while it’s dead it’s not notifying anybody of anything, because it’s dead). So, we need a way for me to get a notification that I have a new email. This requires some sort of native app on the phone, fine, OK, but I didn’t want to have to write a native app to do it; someone must have written an app which can handle notifications and then open up gmail in the web browser. And indeed it is so: on the iPhone there’s Boxcar and Prowl. (I assume there are similar for Android.) Prowl costs money, so I looked at Boxcar first. Boxcar does, indeed, allow you to have it get notifications when you get a new email and then do some sort of user-specified activity when a notification comes in, hooray! (It does this by giving you a magic email address: you tell gmail to forward all your mail to that email address, and when it gets an email, it sends your phone a notification and then deletes the email. This requires trusting the Boxcar people, I agree, but the purpose of this exercise was to see if this could be done at all. If you want security, run your own webmail server, or your own server which monitors gmail and then send the notifications yourself, that’s fine; Boxcar can help with that too via their API.)

the easy bit… is never that easy

So, at this point, when I get an email, Boxcar shows a notification: I press the notification, and it opens my configured URL, which is gmail.com. This is great and I should be done by now, except…Boxcar opens my chosen address in a little in-built web view rather than my browser. Lots of iPhone apps do this — build in a webview rather than using the browser — and it really, really irritates me. There is no option to say “open this in the browser, damn you!” Grr.

But, after some poking around, I notice that the Boxcar changelog says “NEW: Add ability to open custom safari:// URLs in MobileSafari.” Aha! That sounds like what I want. So… I configure my custom URL to be safari://mail.google.com, right?

That doesn’t work. Nor does safari://http://mail.google.com, or any other combination I could think of. There is no documentation other than the above changelog line. Frustrated.

Then I thought: well, it doesn’t have to be Safari, per se. I have Google Chrome on the phone too. Maybe I can use that. The iPhone is set up so that apps routinely register custom URL schemes: it’s how they communicate. Is there, wondered I, some sort of custom URL scheme that I can use to force an https link to open in Chrome rather than Safari?

Indeed there is. Well done Chrome people. If I open googlechromes://mail.google.com it opens https://mail.google.com in Chrome. Yay! So I configure that as my link in Boxcar. Now when I get an email, I touch the notification, and gmail opens in Chrome! Hooray! We’re done!

We’re not done. Now, you see, my home screen link opens in Safari, and my Boxcar link opens in Chrome. That’s annoying and wrong. So, how do I edit the home screen link to be to googlechromes://mail.google.com?

You can’t. You can’t edit a home screen bookmark once it’s created. Bah. So, how do I make Chrome bookmark something to the home screen?

You can’t. Only Safari can do that, because it’s allowed the magic secret APIs and no-one else is.

So how do I put a Chrome bookmark on my home screen? Well, one way would be to have an HTML file which meta refreshes to the googlechromes: URL, and bookmark the HTML file in Safari. That way, I’ll press the home screen icon, that’ll start Safari, Safari will instantly start Chrome, and I’ll have a bookmark. Slightly inelegant, but not too bad.

I stuck the HTML page on my site, and tried it. Minor problem: the page refreshes before I can bookmark it! So, remove the meta refresh, open the page in Safari, bookmark it, put the meta refresh back in again. Ha! That works. (And add a nice home screen icon with <link rel="apple-touch-icon">.

New problem. Every time I hit the home screen bookmark, or the link from Boxcar, we open a new tab in Chrome with gmail in it. After ten minutes of testing this, I’ve got fifteen gmail tabs in Chrome. That’s no good. The Chrome links doc dictates how to explicitly say “I want a new tab”, but not how to say “I don’t want a new tab: reuse the previous one”. After a bit more poking around, though, you can use an x-callback-url-style URL with Chrome, and that lets you specify a source. So, instead of making my bookmark and my Boxcar URL be googlechromes://mail.google.com, I’ll make it be googlechrome-x-callback://x-callback-url/open/?x-source=boxcar&&url=https%3A%2F%2Fmail.google.com. That way, when you open that link a second time, it stays in the same tab as the first time! Hooray!

It’s not perfect. I can’t get Boxcar links and the home screen link to share a tab between them, so I end up with two Gmail tabs in Chrome. That’s annoying but not a total crisis. And this is now clean enough that I can stand to use it for a week. Now I get to actually try using the Gmail web app for a week and see what it’s like!

how annoying is the iPhone?

This all seems like a great big faff to me. Is that all the iPhone’s fault? Well… certainly some of it is. All that crap with Safari being the only thing that can bookmark to the home screen? You can’t add home screen bookmarks that aren’t to real URLs? Sure, these things are fairly technical, but they don’t seem like they’d get in anyone’s way if they did exist. Apparently in older versions of iOS you could bookmark (via a roundabout data URL procedure) weird URLs such as pref:something to open a Settings page directly, and Apple took that away. So that’s annoying.

But in general, I think that the approach of having a server monitor my email and then use the platform’s push notification service to tell me about it and open the webmail client…seems like a good approach. Android does seem to have a couple of IMAP notify apps in the Play Store, but they aren’t reviewed very well, and I don’t really want my phone to hang on an IMAP IDLE socket 24 hours a day. Avoiding that is precisely what push notifications (Google’s “Cloud to Device Messaging”) were invented for. (Note: there are lots of mail notification apps, but they poll. I don’t want polling. When I get an email, I want a notification. Not five minutes later.)

So, then… is this doable on Android? Is there an app like Boxcar where there’s a server component which can (somehow) monitor my gmail account and notify my Android phone, and then pressing the notification on my Android phone will open up https://mail.google.com in the phone’s browser? I’d be interested in hearing the answer to this, Android-using readers.

What about other platforms? How will Firefox OS handle this? (Maybe because they’re all web, they’ll just keep the web page open without ever suspending it, and let it use the web notification API?) I’d like to hear about other approaches. (I don’t want to hear “just use the native app”. Of course that’s the logical thing to do. The point here is to see whether I can set up my life so using a web app for email on my phone is a doable thing. If your answer is “you need to use the native app”, then I’ll take that as you saying “you can’t use web apps for this; you have to go native”. That’s a perfectly reasonable argument, but this post is not directed at you if that’s how you feel.)

Fun little project of gluing together technical bits, I must say. Constraints are the mother of inventiveness!

Customer: "Hi Pete, can I order two of your XP refurbished boxes please?"
Me: "Tell you what, if you order three I'll make you a nice filter coffee when you come to collect."
Customer: "But I don't need three?"
Me: "It's very nice filter coffee."
Customer: "Well I suppose I can put one in the warehouse, go on I'll take three then."

I do like a man who can be bribed with filter coffee.