October 2016 - Roundtable

Ubuntu Muug repo?
by Grigory Shamov 27 Oct '16

27 Oct '16

Hi All, Perhaps a strange question: I mostly use CentOS; and for it there is Muug repo, which is nice and fast and close. Now I am trying Ubuntu : is there a Muug Ubuntu repo, and if yes, what do I put into /etc/apt/sources.list to get it? -- Grigory Shamov Westgrid/ComputeCanada Site Lead University of Manitoba E2-588 EITC Building, (204) 474-9625

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wacky NFS port problem
by Trevor Cordes 24 Oct '16

24 Oct '16

OK, this is a new one... Updated my kernel and rebooted tonight. Everything came up fine. Except dovecot (IMAP server). It complained: Error: service(imap-login): listen(*, 993) failed: Address already in use (993=imaps) OK. Except: #netstat -tulpn | grep 993 <nothing> #lsof -i:993 <nothing> #ss -t -l 'sport = 993' <nothing> A wasted hour later I did: netstat -n |grep 993 Sure enough I had a tcp connection between my workstation and my file server on 993 to 2049. grep 2049 /etc/services... eureka! 2049 is nfs. >From what I've figured out, nfs, which I have mount something on boot, randomly grabbed 993 before dovecot did, and was holding it as long as the nfs fs was mounted locally. And because nfs is in-kernel it didn't show up in lsof et al. I umounted it, waited for TIME_WAIT to expire and then I could start dovecot. *** This has never happened before on dozens of reboots... I guess it's pretty much luck / race condition what port nfs gets, especially with systemd possibly trying to do the mount and/or dovecot in parallel. I have no idea when it tries to do the mounts, but I'm guessing before dovecot. Note, I'm using NFSv4 which (unlike older NFS) uses TCP stateful in a persistent connection. Pretty much everything you know about v2/v3 throw away when it comes to using v4. I poked around nfs docs and google and found this option: resvport / noresvport Specifies whether the NFS client should use a privileged source port when communicating with an NFS server for this mount point. If this option is not specified, or the resvport option is specified, the NFS client uses a privileged source port. If the noresvport option is specified, the NFS client uses a non-privileged source port. This option is supported in kernels 2.6.28 and later. Refer to the SECURITY CONSIDERATIONS section for important details. OK, down there is a section: Using non-privileged source ports Which basically says using privileged ports is for security so normal users can't make/fake their own daemons and pretend to be any user they want. OK, so I know that's a bit hokey from a sec standpoint, but it's better than nothing, I guess. Regardless, having nfs client pick a random high port might hurt me also because I use some of them for my own purposes/daemons and I need them open also. The docs say this: "The exact range of privileged source ports that can be chosen is set by a pair of sysctls to avoid choosing a well-known port, such as the port used by ssh." Which would be perfect, except I can't find any further reference to these magic sysctls. I tried searching my box's /proc and /sys fs's for nfs & ports, nfs & priv, nfs & mount, etc. Couldn't find anything relevant. It would be really nice if I could specify the local source port, or at least specify the list of no-no ports using this elusive, promised, "sysctl". Anyone have any ideas? What a strange bug to run into. Chance of 1 in 1024 and it had to hit me.

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Re: [RndTbl] Ubuntu desktop vs server - UNISON
by jd 21 Oct '16

21 Oct '16

NOT gui, but worth a squint: UPenn.edu 's UNISON USES rsync (dependency; also ssh) IT WORKS no matter which way you've installed your Linux host server. AS WITH rsync (good example, Trevor), BEWARE "direction" .. "who's the boss" .. TEST: definitely set up HERE://~/exampleDir/ _ and There://~exampleDir/ with files like, say: OrangeFile,BlueFile,GreenFile in SOURCEdir (Here) and YellowFile, RedFile in DESTINATIONdir (There) and LEARN that a) you've either config'd "direction" properly, .. or .. b) you've clobbered DESTINATION, 'coz it's pushing wrongway. Seeing is believing. "ALLOWING" unique items to survive sync, at destination, which do NOT exist at source, is tricky. Somewhat eased configs, telling Unison how to behave, after initial setup/test session. Then we can (sudo) edit its config file; /root/.unison/default.prf ADVANTAGE rsync: Cordes' example here, is just as strong a starting point (and rather more concise). Please note that files in your system with extended file attributes will come across better with rsync. ADVANTAGE Unison: it is platform independent. So, you can dodge dissimilar syntax/vagaries where rsync talks between dissimilar platforms. e.g: WinX .. to Linux .. Or .. OSX .. to WinX .. Or .. Linux to .. etc Here is a Unison tutorial: https://www.howtoforge.com/tutorial/unison-file-sync-between-two-servers-on… That tutorial establishes an ssh encrypted connection. If one of your hosts is anaemic (slow CPU) stay with rsync, and without ssh/encryption. Re: TEXT EDITING of config files - "vi" is always present on a unix system - you want to learn it, but not in a hurry. PRACTICE is NECESSARY "nano" (I believe) is present in default Ubuntu/Mint install - less cryptic, less landmine kbrd Note: Tutorial installs nano. IN EITHER CASE - practice text editing from Command Line Interface "CLI" REMEMBER the folder/path/folder/path delimiter is 'slash' .. NOT backslash ASIDE: One would vote we never again refer to 'slash' as 'forward slash', to avoid needling from the greybeards THESE UPenn people who set up Unison, I believe, did it for simplicity (not just xPlatform). YMMV. DISADVANTAGE UNISON: THESE OXFORD pointyheads are NO LONGER ENAMORED with Unison, and give very good examples for obscurities of rsync; e.g: using wildcard star/asterisk/"*" will miss .dotFiles https://www2.physics.ox.ac.uk/it-services/how-to-use-rsync John D

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Ubuntu desktop vs server.
by Justin Richard 20 Oct '16

20 Oct '16

Hi. I'm honing to sound like a total noob here but please have patience I'm trying like hell to catch up. Lol. I'm about to setup Rsync to transfer files to a backup machine. So I'm looking around the internet for people's best practices and opinions. I'm noticing that many of the admins are doing things in a combo of GUI in desktop and cmd line opposed to strictly cmd line in server. I'm from the Windows world and I think that having a point and click environment would help me move quicker. Can you guys tell me why I wouldn't want to use Ubuntu desktop? Or is there a better desktop to use for admin tasks? Thanks in advance. Justin.

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NEW: Catch up with Muug meetings online.
by Wyatt Zacharias 15 Oct '16

15 Oct '16

Hey everyone, we're trying something new for our monthly meetings and putting video recordings of the daemon-dash/RTFM and presentation segments to watch on youtube, and the muug website. If you missed the meeting, or would like to watch part of it again, you can go to https://www.youtube.com/channel/UCOhDmKEXk9oUJActy_u4cUA or https://muug.ca/meetings/video to find them. -- Wyatt Zacharias

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IBM "clicky" keyboards
by Adam Thompson 13 Oct '16

13 Oct '16

Enough people have wondered/asked/complained to me about this that I'm posting this now as a public service. IBM Model "M" keyboards are still available, *NEW*, today. They are expensive, but they are the original design that you can use as a melee weapon. The catch is that they don't say "IBM" or even "Lexmark" on them. They are available for purchase from the manufacturer, Unicomp, who can be found online at http://www.pckeyboard.com/. You can also find some vintage NIB units from time to time at http://www.clickykeyboards.com/. There are also a number of other manufacturers now making similar, but not quite as good, keyboards. - CVT Inc., the maker of the Avant Stellar (I own two of them), which is the direct descendant of the Northgate Omnikey, seems to have restructured and no trace of their keyboard manufacturing operation can be found online. However, Northgate keyboards are still available new-in-box from (this is a horrible site, beware) http://www.northgate-keyboard-repair.com/. - The Happy Hacking keyboard (now owned by Fujitsu, apparently) is equally comforting to some people despite having a totally different feel. They, and many others, can be had from http://www.elitekeyboards.com/ - Das Keyboard - Anything using Cherry MX Green, Blue, or White keyswitches. The "green" switches apparently are the closest anyone's come yet to emulating the IBM/Lexmark/Unicomp switches... and they can be had in MUCH cheaper keyboards, like the Rosewill RK-9000 (http://www.newegg.ca/Product/Product.aspx?Item=N82E16823201040 and http://techreport.com/review/23405/rosewill-rk-9000-series-mechanical-ke yboards-reviewed). - And there are an increasing number (yes, again, after the big die-off ca. 2009) of speciality manufacturers of "ergonomic" keyboards that are making clicky keyswitches available as an option. One of the better ones is a tiny shop in Ontario, but I can't find the name right now. References: http://en.wikipedia.org/wiki/Model_M_keyboard http://en.wikipedia.org/wiki/Unicomp http://deskthority.net/wiki/Cherry_MX -Adam Thompson athompso(a)athompso.net

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Current and recent cool-running Intel and AMD CPU's
by Hartmut W Sager 13 Oct '16

13 Oct '16

Does anyone here know how to accurately identify current and recent cool-running Intel and AMD CPU's by their model/chip designations? I hope the family of cool-running CPU's that started with Intel Centrino and AMD Turion still exists. All 3 of my well-dated laptops (2006-2009) have AMD Turion x64 dual-core CPU's, and those laptops are still running quite cool and quietly with the fan only occasionally kicking in. In the meantime, my friends and colleagues with laptops featuring high performance high GHz CPU's have heat-fried quite a few of them, typically with a 2-3 year lifespan. So, if and when I shop laptops again, I'd like to continue with cool-running CPU's. (Yes, I know there's a GPU heat issue as well.) Hartmut W Sager - Tel +1-204-339-8331, +1-204-515-1701, +1-204-515-1700, +1-810-471-4600, +1-909-361-6005

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dell pe 860 rails
by Theodore Baschak 12 Oct '16

12 Oct '16

I'm looking for some rack rails for a dell poweredge 860. Does anyone local have some? Shipping on those things is always more than the item itself. Theodore Baschak - AS395089 - Hextet Systems https://ciscodude.net/ - https://hextet.systems/ http://mbix.ca/

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MUUG Meeting, October 11, 7:30pm -- Physical Computing
by Gilbert E. Detillieux 10 Oct '16

10 Oct '16

The Manitoba UNIX User Group (MUUG) will be holding its next monthly meeting on Tuesday, October 11. The meeting topic for this month is as follows: Introducing Physical Computing Davidian Chorley will be our presenter this month. Introducing Physical Computing is a presentation on computing devices with GPIOs. General Purpose Input/Outputs allow interfacing with a huge variety of hardware. Davidian will discuss several platforms that implement GPIOs, why one might want to use them, his own projects and various common and creative uses for physical computing. Platforms covered are Raspberry Pi and Raspbian (Debian), Arduino (the device and IDE), and MBED programable devices from the ARM processor platform. Daemon-Dash: tinc For this month's Daemon-Dash segment, Mark Jenkins will present [13]tinc, "a Virtual Private Network (VPN) daemon that uses tunnelling and encryption to create a secure private network between hosts on the Internet." Door Prizes On top of whatever else is on offer this month, we'll have a copy of "The Book of JavaScript", 2ed, by No Starch Press as a door prize. There will also be a Raspberry Pi Model B+ being drawn. The group holds its general meetings at 7:30pm on the second Tuesday of every month from September to June. (There are no meetings in July and August.) Meetings are open to the general public; you don't have to be a MUUG member to attend. ****************************************************************** Please note our *NEW* meeting location for this month: *Room 1M28* (1st floor) Manitoba Hall, University of Winnipeg, entrance on Ellice Ave. between Spence St. and Balmoral St. Parking is available on the surrounding streets and in the lots on nearby streets. Look for signage once you're at the building, or ask a security guard. ****************************************************************** For more information about MUUG, and its monthly meetings, check out their web server: http://www.muug.mb.ca/ Help us promote this month's meeting, by putting this poster up on your workplace bulletin board or other suitable public message board: http://www.muug.mb.ca/meetings/MUUGmeeting.pdf -- Manitoba UNIX User Group E-mail: <gedetil(a)muug.mb.ca> c/o Gilbert E. Detillieux Web: http://www.muug.mb.ca/ University of Manitoba Phone: (204)474-8161 Winnipeg MB CANADA R3T 2N2 Fax: (204)474-7609

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muug mirror - openbsd 6.0
by Theodore Baschak 10 Oct '16

10 Oct '16

Looks like the muug.ca mirror doesn't have OpenBSD 6.0 which was released Sept 1st Theodore Baschak - AS395089 - Hextet Systems https://ciscodude.net/ - https://hextet.systems/ http://mbix.ca/

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