SKS deployment on Debian (my way...)

Deploy the Debian LXC template from ProxMox

(Oh, I need somebody to help me with the needed theme/etc. to have the Blogger editor/etc. provide me nice [code] type formatting)

check and make sure the networking/firewalls/etc. works
add a
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/sks resource/mountpoint
Install byobu:

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dpkg-reconfigure locales #Select UTF-8 apt-get install byobu sudo apt-get purge nano #I hate that editor ;( VI! visudo #for NOPASSWD (Like I do) useradd -m USER passwd USER chsh -s `which bash` USER vi /etc/group (add user to sudo group) passwd USER copy ssh keys (I usually does it with ssh-copy-id) passwd -l USER (USer without password, only ssh) byobuRight now you can do the rest in byobu/etc. [/pre] [pre class="prettyprint linenums"]
sudo su - echo "deb stretch-backports main contrib" /etc/apt/sources.list.d/backports.list apt-get update apt-get dist-upgrade -y apt-get install -y zlib1g-dev libdb5.3-dev curl build-essential ocaml procmail socat #I also need some newer that stock stretch versions of: apt-get -t stretch-backports install nginx-extras sshguard [/pre] [pre class="prettyprint linenums"] useradd -m -s `which bash` -d /sks/home sks sudo su - sks wget tar -axvf sks-1.1.6.tgz cd sks-1.1.6/ cat << EOF > Makefile.local BDBLIB=-L/usr/lib BDBINCLUDE=-I/usr/include PREFIX=/sks2/sks LIBDB=-ldb-5.3 MANDIR=/sks2/sks/share/man export BDBLIB export BDBINCLUDE export PREFIX export LIBDB export MANDIR EOF [/pre]

Systemd and the mount of pain

I wish I didn't have to complain about systemd.

I wished it would work from system administrators' perspective.

I wished it wasn't convoluted.

I wished I didn't wish...

The problem

I've been looking for HA, across VMs, solutions for remote-shared filesystems. The specific case in point, is a django webservice, that we've needed to split across VMs, that writes to a "local" filesystem, which it then pass on to NGinx/Apache to servbe the specific file from it's filesystem. The Nginx/Apache have been split across VMs for HA reasons too, so I need a NFS/CIFS/etc. filesystem to share the files, and to have it spread across datacentres inside VMs. (less than 100GBs of images and thumbnails, though it's growing).

The first (failing) solution

The solution, after researching various options, like CEPH, DRBD etc. was (initially) setttled on NAS4free, using FreeBSD's HAST for a shared/duplicated block device and using CARP to fail over the service virtual IP (VIP). The system was installed, though a bit finicky, and was "working", however, it has a gory splitbrain problem since it it split acros datacentres, and it also have the problem that it's 2 nodes *only* for HAST! ie. I can't setup a quorum disk, and right there the fun started when the two datacentres experienced some latency and CARP kicked in an the slave becomes master... and then we have split brain. HAST is best for two nodes physically next to each other with STONITH options, NOT for my case of remote VMs ;(

The reason I chose it, was because of my preference to ZFS, and it was an "easy" ZFS on top of the HAST, and I got it going quickly as we was under a bit of over-run constraints.

Let's relook and re-investigate

I've considered the other options, and the main options could be classified as such:

Shared block device cluster filesystems

This type of cluster/shared storage, shared a common device, and they have locking features to prevent simultaneous accesses. The assumption here is both servers write to the same disk/block-device. Not quite usefull for the distributed VM case, unless you use a distributed block device (like DRBD)

Distributed block devices

Here the "disk" is distributed, and the writing to the block is typically in a active/passive setup where only one server have access to write to the disk, and you'll have to fail over to the slave and start/mount the needed services once failure is needed. This way you can use any filesystem on top of it. This is the HAST solution, and the DRBD in "normal" setup. The problem with is a single server is active on it, and could become a bottle neck, and service failover needs to be handled.

To have a multiple server active/active to this, you will need a cluster aware filesytem as above. HAST doesn't have active-active, which then gives DRBD and CEPH's 

to HTTPS or to HTTP?

I have to say that HTTPS makes sense in environment where there is a need to protect and HIDE the information inside the communications channel. Examples for this being banking or financial transactions as well as passwords.And even here I'll make a claim that I not utterly convinced beyond all doubt that HTTPS is the best option method to protect those data...

But does it make sense to encrypt EVERYTHING? like what is trying to achieve? (Okay, I'm all FOR the cheap/free SSL certificates, but... but ... it won't solve it all)

No it doesn't. Let me give you an example where encryption is not only a pain in the back, but counter productive: Package distribution.

Firstly I'm typically in situations where I need to reload/reinstall packages to test reliable recreation of systems. However, I'm also limited to costly internet connections, so I want to cache the packages, simply setup something like squid ro apt-cacher-ng, and I'm set.... except for those that does https:// <ARGH!!>

Let me explain, the first problem you'll hit is that apt-cacher-ng doesn't do the CONNECT statement for proxies, and why should it? it should cache the data, not bluntly allow a tunnel. I'm not even going to explain, but you'll see it in various ways and means, and I don't believe it's the right thing, as simply put it this way: I could still capture (ala's SSL) your connection (since you are behind *my* firewall and proxy) and I could abuse some CA issues and then I'll be able to make you think you are connecting to the right place. But besides that, what are we actually hidding in that transaction? It boggles my mind, but let's continue.

The main concern with regards to package distribution, is the reliability of the package downloaded, and that that downloaded package haven't been tampered with. You know that this problem have been solved and used for the past 20 (twenty) odd years now? Simply sign the package with your GnuPG key, and distribute your public key, and then everybody can check that the file recieved, is the actual file that you've signed. This is as secure, if not better, than trying to trust CAs out there in the wild to confirm that your HTTPS connection was the right HTTPS connection you've said it was.... and then I'm still not sure if the file on my disk haven't been tampered with while it was busy downloaded...


Yours loving encryption himself

iPXE pxeboot and Linux (The 40+ year old explanation)

Okay, I'm over the hill, and it starts to show, but after a morning's caffeine usage to get to the gist behind it, here are a few pointers and experiences to get a tutorial going.

  1. You are intelligent enough to setup tftp server
  2. Your brains don't freeze on a DHCP server's config files
  3. You are purveyed with tcpdump, dhcpdump and strace
  4. You can configure and server HTTP pages with whatever means you like.

Thus, I'm not going to detail the above to bore nor confuse, but rather help you with the iPXE understandings (and freshening your linux kernel parameters :) )

The other assumptions:

  • You have a PXE enabled BIOS/network adapter and want to chainload iPXE from it with a UNDI stack
The basic idea/process:

  1. Have your PXE network adapter, get a DHCP IP and information about the next image to load. This will be undionly.kpxe (You could do an ipxelinux.0, but that's adding complexity for now)
    1. The normal PXE understands TFTP, so you'll add the following parameters to give to the client:
    2. next-server "ip_of_tftp_server";
    3. filename "undionly.kpxe"
and right here I fell asleep and decided I'll wait for the digital KVM module for the Dell 1955 blades...

MS Powershell: The blessed curse

Right, well where do I start? I had to do scripting and scheduling on Windows Server 2008R2SP1 (don't ask, but at least it's not 2012).
Good, RTFM a tad, then found this new thing that just rocks in the Windows world called PowerShell! It's the best thing that perhaps could've happen in the Windows server world since... since... since... NT 3.5.1? Okay,  NT 4 was nicer and W2K looked polished, but ... but... they've always missed that one ingredient that is loved by the Un*x SysAdmins: A decent shell with scripting that doesn't suck like .BAT batch files. PowerShell 2.0 is that missing element! (And 3.0 added the remote management lmuch like what we Un*x SysAdmins used to do with SSH... It rocks, I'll admit that, and it does a few things better with it object model compared to the plain-ol' character strings in the Un*x world... it has it down falls too, but on average, I'll say I do like what they've done with PowerShell up to 4.0 (haven't yet loaded 5.0... as I don't think it'll run on my 2008R2 servers...)

But, let's get to my curse for the day: Scheduling and PowerShell (and a non-encore: schtask.exe)

Windows have this "fancy" thing called "Windows Task Scheduler". Quite extensive in what/how/etc. you have to tweak and turn, just I'm missing the documentation and the flow diagrams to explain when what will or won't work, but that's still "manageble". The fun is that PowerShell have cmdlets and scheduling that nicely fits into the Windows Task Scheduler... except that it doesn't open up all the Task Scheduler functionality *I* want and need ;(

I have the need for the period 07:00-18:00 to execute a PowerShell script every 5 minutes ( I wanted 1 minute intervals as my actual need is around a on-demand wake up when somebody drops/rename/change a file and any file in a certain directory)... Nope, the standard PowerShell job scheduling doesn't have that function, but there are several other ways people use a start job to do things like that, but that is just adding way too much complication in my live (Oh, then there are the COM object direct manipulation... I'm not going that way today, and the Task cmdlets appears to be 2012 specific ;()
But don't worry, schtasks.exe (DO notice the taskS there O_o) is there! Well... it's not so easy as telling it to execute D:\scripts\Send.ps1, no, that is way too easy and we'll have to make life difficult, so they threw a spanner in the works that it starts NotePad.exe... NotePad.exe?? Googling didn't show me anything related, so I checked the script, executed the script etc. but it all works as advertised in the PowerShell ISE... until I got the strange idea in my head: try the script in cmd.exe... VOILA! it opens a notepad.exe with the contents of the script. The Problem: Windows doesn't have a She-Bang (#!/bin/powershell.exe) like in Un*x scripts, so... well... let's just say, test you schtask.exe & at.exe script executions using cmd.exe before deploying/test on schtask.exe or at.exe, as you'll need something like "powershell.exe <script_path_name>"

Well... I don't need any deeper knowledge, as the scripts work (good enough for what we should be doing with them) and the timing appears to be adequate, so let's move on to the next problem in this project.

Blogging templates

Blogging has not been the "thing" for me, other than to blow of steam, but I want my blog to look sorta the way *I* want it to look like... let's not yet get into privacy for me using... okay let's get to the point.

I want to just slightly modify the layout. I want a right hand sidebar, with a 2-1-2 layout, ie. 2 widget next to each other, then a single wide widget, and eventually 2 more widgets next to each other... that's easy, just a bit of <div>ing and all should be fine! Oops, it's a whole "template language" itself, so let's try to dissect it. So I delved into it and found the <b:section-contents..>, their xml closing tags, the <b:widgets..> with their closing tags, I massged their positioning, their numbers and NON-voila!

I got a section with id "sidebar-right-1-1" does not exist error when trying to save/upload/restore the newly created XML. Time to use Blogger's search pal Google: Nothing, nada. Okay. let's debug the code and search for sidebar-right-1 (which was the original tag/id) NADA!
 Right, Let's Google some different tack about the template language, and up pops a "teplate from scratch" describing a <b:section class= id=> tag. Searching for that, I got this line:

    <b:section mexpr:class='data:col.class' mexpr:id='data:col.idPrefix + &quot;-1&quot;' preferred='yes' showaddelement='yes'/>
 Now, please somebody try to tell me where in the code I can find those mexpr: as it looks like one of those fancy Javascript includes needs to be dissected to find what and where and how this template have been desgined. 

 Let's rephrase this: Hevisko, you want your own template layout, go learn Javascript, jQuery, Ajax, <insert caffeine addiction of choice><framework of choice><scripting language of choice>, CSS, HTML and sanity --- in that specific order.

Mac OSX settings to not forget

[pre class="prettyprint"] sudo spctl --master-disable [/pre]