main September 2014

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25 participants
31 discussions

Linux Job - Devops/Sytems Engineer - Cambourne/Cambridge. £35k-£45k
by Adam Bower 23 Sep '14

23 Sep '14

Hi all, I currently work for http://www.swiftserve.com and we're recruiting for at least one and possibly 2 Linux systems/devops engineer positions. I've attached the job description below, sorry about the formatting. Currently we're based in Cambourne but we're moving to Milton in January. This is a permanent position and we're wanting people to start as soon as possible. Salary is in a range from £35k-£45k, possibly a bit more for exceptional candidates. If you want to send an application or have questions then please send a CV/email to my work email address: abower(a)swiftserve.com Description: We are looking for a Dev Ops engineer with strong Linux skills to work on automation, deployment, monitoring, integration and investigating complex issues. Responsibilities: The successful candidate will have overall help work closely with our Engineering and Operations teams to help improve our automation, packaging, continuous integration and monitoring across our PaaS offerings. Will help work with our field engineers and support teams to investigate complex issues and design and architect customer solutions to meet customers needs. Investigate complicated issues, debugging distributed systems involving multiple components to isolate problems. As part of investigation it is expected that this person will be able to reference the source code to understand what is going on, and perform investigations involving packet dumps, log files and monitoring data from multiple systems. Work with engineering and product leads to provide feedback on to the product into areas where it can be improved and enhanced. This role will involve some out-of-hours work on deployments and/or on-call rotas. Experience/Skillset Required: Excellent Linux skills - solid background in systems administration, knowledge/experience of investigating issues and bottlenecks. Strong understanding of Internet networking covering IP networks, Internet protocols and technologies, packet dumps. Good basic programming experience, able to write and understand programs in a variety of languages with experience of Python (or at least Python-like languages such as Ruby or Perl) and Javascript. Experience of using Unix tools to help analyse log files (e.g. use of tools like ‘awk’, ‘grep’, ‘uniq’) Experience of using automation tools for deployment (e.g. Puppet or Chef) and monitoring tools. Experience of using/building network monitoring and alerting systems. Experience of Linux software packaging (e.g. building RPMs or DEBs) Pragmatic and flexible attitude, and a desire to solve the customer requirement. Fluent English speaker with good written and verbal communication skills. Able to work in the UK (EU citizen or existing work permit), and able to work predominantly in our Cambourne office. Useful Knowledge of video-related technologies covering encoding (transcoding), protection (DRM) and delivery protocols (HLS, HDS, Smooth, RTMP) Basic understanding of C, C++ and Java. The Company We are a self-funded and established start-up employing about 35 people around the world. We are tackling the challenges around the delivery of large volumes of data (e.g. video) over the Internet. As such we provide content delivery services to some of the largest networks in the world and are responsible for service provision with extremely high uptime requirements. Thanks Adam

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How to change ssh destination depending on connected LAN?
by Chris Green 23 Sep '14

23 Sep '14

As I move around from home to various other places different systems that I connect to from my laptop become 'local'. Being a lazy person I really don't want to type in long complicated ssh commands when I'm connecting remotely. Thus I have in the ~/.ssh/config file the following:- Host cheddar HostName cheddar.halon.org.uk Host halon HostName cheddar.halon.org.uk Host chris ProxyCommand ssh cheddar nc -q0 zbmc.eu 22 Host odin ProxyCommand ssh cheddar nc -q0 localhost 51234 This means I can simply type 'ssh chris' or 'ssh odin' and ssh with the above config file does all the hard work for me. However it means that when I'm at home for example (where 'chris' is my desktop on the LAN) if I type 'ssh chris' I get connected to my desktop machine via the internet which is rather ridiculous. Can anyone come up with an easy way to change how 'ssh chris' acts according to whether I'm on the LAN where 'chris' is or not. Similarly I want the same to happen when I'm on the LAN where 'odin' is (which is not the same LAN). -- Chris Green

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Re: [ALUG] How to change ssh destination depending on connected LAN?
by Chris Green 22 Sep '14

22 Sep '14

On Mon, Sep 22, 2014 at 01:58:00PM +0100, Laurie Brown wrote: > On 22/09/14 13:49, Chris Green wrote: > > [SNIP] > > > As I have pointed out in a previous reply this doesn't work because of > > the ProxyAddress stuff I have in my ~/.ssh/config file. I need some > > way to switch the ProxyCommand off when I'm on the LAN. > > Why not have two such files, each specific to a particular location, and > write a bash script with a parameter to copy over your ~/.ssh/config > file whichever version you need? I really don't understand the problem here. > Fine, it's just the sort of thing I was thinking of doing. My question was really how to automate the switch over by (somehow) detecting whether I'm connected to the LAN or not. -- Chris Green

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Re: [ALUG] How to change ssh destination depending on connected LAN?
by Chris Green 22 Sep '14

22 Sep '14

On Mon, Sep 22, 2014 at 10:38:42AM +0100, mick wrote: > On Mon, 22 Sep 2014 08:52:26 +0100 > Chris Green <cl(a)isbd.net> allegedly wrote: > > > On Sun, Sep 21, 2014 at 11:25:23PM +0100, steve-ALUG(a)hst.me.uk wrote: > > > On 20/09/14 13:19, Chris Green wrote: > > > >As I move around from home to various other places different > > > >systems that I connect to from my laptop become 'local'. Being a > > > >lazy person I really don't want to type in long complicated ssh > > > >commands when I'm connecting remotely. Thus I have in the > > > >~/.ssh/config file the following:- > > Sigh. > > Chris > > Why do you keep asking variants of the same question? Lots of different > people have taken the time and effort to answer those questions for > you at various times in the past, yet you ignore the answers and come > back with yet another variant of the "how do I do this when connecting > to/from my boat"? > Please read the question! :-) It's very much *not* the same question as I've asked before. The specific issue is because of my use of ProxyCommand in my ~/.ssh/config file. It's *not* "how do I get local names to work". -- Chris Green

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mp3splt and regex
by Chris Walker 22 Sep '14

22 Sep '14

Hello, I'm struggling to split an mp3 file and simultaneously enter some tags in to the output. The input filename which is a get_iplayer download looks like this 'David_Rodigan_-_02_09_2014.mp3' and my problem is adding tags to the output. How do I make 'David_Rodigan' appear as 'title' in the output tags? I guessed that David would appear as first_part and Rodigan as second_part but I can't see a way to concatenate those two items to form title. My attempt looks like this :- mp3splt -G (?<title>):first_part+" "+second_part David_Rodigan_-_02_09_2014.mp3 3.00 60.00 -o /split/David_Rodigan_-_02_09_2014 But that fails with bash: syntax error near unexpected token `(' I'm looking at this page for inspiration but it isn't helping! http://mp3splt.sourceforge.net/mp3splt_page/documentation/man.html Perhaps somebody here can explain where I'm going wrong please? -- __ __| |_ __ __ .----------------------------------------------. / _/ _` \ V V / | mailto:alug_cdw@the-walker-household.co.uk | \__\__,_|\_/\_/ |______________________________________________|

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Any idear how this router running Linux configures itself?
by Chris Green 21 Sep '14

21 Sep '14

I have a little Solwise 3G router on my boat. I have just discovered it runs Linux and I can telnet into it. Even better it runs dnsmasq so, if I can configure it appropriately then I can get it to provide local DNS. However I can't work out where it configures itself from at boot time. If I edit /etc/hosts for example then, if I reboot, my changes are lost. There's an /etc_ro directory but nothing really much in there gives a clue. There's even an /etc_ro/rcS file which is obviously executed fairly early on in the boot sequence but it's not early enough to indicate where the basic configuration lives. The motd file says:- ------------------------------------------------------ Welcome to HAME Technology Co.,Ltd =System Architecture Department= ------------------------------------------------------ ... oh, it as busybox for most of the commands. Does anyone have any idea how it starts up and configures itself? -- Chris Green

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Is there such a thing as a 'WiFi switch' to add WiFi to a LAN - if so what's it called?
by Chris Green 18 Sep '14

18 Sep '14

I'm not even sure such a thing exists but it feels as if it ought to. I want a 'WiFi switch' that I can plug into an existing LAN such that it allows WiFi access on the *same* subnet. Thus it won't do anything clever like DHCP or DNS or anything as that will be done by existing devices on the LAN. All the 'range extenders' I can find are WiFi both in and out and also tend to create their own subnet. Anyway I need something that hangs on a hard-wired ethernet connection. Is there such a thing? -- Chris Green

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Ubuntu startup scripts
by Mark Rogers 17 Sep '14

17 Sep '14

Where are the various places that processes can be started on desktop login on Ubuntu? Specifically: My laptop has an encrypted Truecrypt partition, and a Dropbox share on it. On login Dropbox tries to start and can't access its directory because at that point I haven't mounted the TC volume. Dropbox is listed in the Startup Applications GUI, which as far as I can tell just lists whatever is in ~/.config/autostart. However, if I remove it from there (either from the GUI or by deleting dropbox.desktop, and with Dropbox stopped when I do it), if I log out and back in again it puts itself back and starts again. Where is that coming from? Furthermore: if I replace dropbox.desktop with an empty read only file, it doesn't get replaced but Dropbox still starts. How? Further furthemore: I have my own bash script which prompts me for the TC volume password, mounts it, then starts dropbox. I have added that to ~/.config/autostart (via the GUI), but my script doesn't seem to start. What might I be doing wrong? Over the years I have spent ages removing viruses on Windows and got used to the idea that there are dozens of places that you can configure applications to start automatically but I thought Linux would be a bit cleaner than that! This has prompted me to learn more about the startup process. -- Mark Rogers // More Solutions Ltd (Peterborough Office) // 0844 251 1450 Registered in England (0456 0902) @ 13 Clarke Rd, Milton Keynes, MK1 1LG

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Simple way to find local subnet?
by Chris Green 16 Sep '14

16 Sep '14

Is there a simple way to get the value of the local subnet to which one is connected? I know I can derive it from what ifconfig outputs but using grep to get '192.168.13.0' from output like:- eth0 Link encap:Ethernet HWaddr f0:de:f1:2b:f9:13 UP BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:1533 errors:0 dropped:0 overruns:0 frame:0 TX packets:2135 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:820119 (820.1 KB) TX bytes:231948 (231.9 KB) Interrupt:20 Memory:f2500000-f2520000 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:1181 errors:0 dropped:0 overruns:0 frame:0 TX packets:1181 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:126765 (126.7 KB) TX bytes:126765 (126.7 KB) wlan0 Link encap:Ethernet HWaddr 00:24:d7:6e:3d:08 inet addr:192.168.13.104 Bcast:192.168.13.255 Mask:255.255.255.0 inet6 addr: fe80::224:d7ff:fe6e:3d08/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:8144 errors:0 dropped:0 overruns:0 frame:0 TX packets:8180 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:3358385 (3.3 MB) TX bytes:1152063 (1.1 MB) .... seems a little more difficult than it should be. Presumably arp-scan does it somehow when you use 'arp-scan -l'. -- Chris Green

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Thunderbird oddness
by Bev Nicolson 15 Sep '14

15 Sep '14

Thunderbird seems to be selective about which emails it marks as replied to with the blue arrow now so I'm uncertain whether they've been sent or not. I haven't changed any settings so does anyone know why this might be? (24.2.0) Bev.

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