Tag Archive for fix

Index of Tekhead.it Blog Posts on Amazon AWS

I wrote my first blog post on AWS in February 2016 and the series is growing pretty quickly, so I thought it was worthwhile indexing all of the current posts and providing an updated list as this grows.

Hopefully, this should make these posts a little easier for people to find in the future!

Anyway, enough gabbing, on with the posts and links:


Podcasts

I was kindly invited by Scott Lowe to join him on the Full Stack Journey podcast, to discuss learning AWS and cloud architecture. The episode can be accessed here:

AWS Certification

bill was study Certified SysOps Administrator

AWS Tips and Gotchas Series

Random AWS and Cloud Related Posts

Also, just in case I forget to keep this page updated:
http://tekhead.it/blog/category/aws/

AWS Tips and Gotchas Blog Posts

Installing Docker on Amazon AMI Quick Fix

Docker Logo

I was installing and playing with Docker on an AWS EC2 instance this evening, using the default amazon AMI [specifically Amazon Linux AMI 2015.09.1 (HVM)] and came across a stupidly simple issue.

Docker containers would not start and were showing the following error:

Cannot connect to the Docker daemon. Is 'docker -d' running on this host?


Checking processes I don’t see docker running:

$ ps -ef | grep docker
ec2-user  2518  2485  0 22:20 pts/0    00:00:00 grep --color=auto docker


After looking at a similar issue I had with Ubuntu a year or so ago, I realised (duh!) the Docker service was simply not running, even though it had installed fine.

A quick start of the service fixed this:

$ sudo service docker start


And now…

$ ps -ef | grep docker
root      7119     1  1 22:30 pts/0    00:00:07 /usr/bin/docker daemon --default-ulimit nofile=1024:4096
ec2-user  7539  2429  0 22:41 pts/0    00:00:00 grep --color=auto docker
$ sudo docker info
Containers: 1
Images: 4
Server Version: 1.9.1
Storage Driver: devicemapper
 Pool Name: docker-202:1-263816-pool
 Pool Blocksize: 65.54 kB
 Base Device Size: 107.4 GB
 Backing Filesystem: xfs
 Data file: /dev/loop0
 Metadata file: /dev/loop1
 Data Space Used: 291.9 MB
 Data Space Total: 107.4 GB
 Data Space Available: 6.695 GB
 Metadata Space Used: 892.9 kB
 Metadata Space Total: 2.147 GB
 Metadata Space Available: 2.147 GB
 Udev Sync Supported: true
 Deferred Removal Enabled: false
 Deferred Deletion Enabled: false
 Deferred Deleted Device Count: 0
 Data loop file: /var/lib/docker/devicemapper/devicemapper/data
 Metadata loop file: /var/lib/docker/devicemapper/devicemapper/metadata
 Library Version: 1.02.93-RHEL7 (2015-01-28)
Execution Driver: native-0.2
Logging Driver: json-file
Kernel Version: 4.1.10-17.31.amzn1.x86_64
Operating System: Amazon Linux AMI 2015.09
CPUs: 1
Total Memory: 995.6 MiB

 

This has now continued to work fine through reboots, so hopefuly saves someone spending more than a few seconds troubleshooting!

NanoLab – Part 10 – Your NUCs are nice and cool, but what about your stick?

I have been running a variety of Intel NUC nodes in my vSphere homelab over the past 3 years now, including the D34010WYKH, DC3217IYE & DC53427HYE.

In that time I have unfortunately seen more than my fair share of USB drive failures and corruptions, generally with an error which looks something like this:

Error loading /k.b00
Fatal error: 33 (Inconsistent data)

 
These are not cheap and nasty, or freebie USB drives, so I would not normally expect to see this rate of failures. The error only occurs when you reboot the host, and the startup bombs out at the start of the hypervisor launch. I have often managed to recover the stick by copying back corrupted files from another instance, but generally I needed to rebuild and restore the image. An unnecessary pain in the rear!

The Root Cause
The NUC case can become quite warm during normal operation with or without the fans spinning up, and I have come to believe that the main reason for the corruptions is that the USB stick itself is getting too hot and therefore eventually failing. Having pulled a USB out from a recently shut down node, they are really quite hot to the touch. You don’t actually see the symptom / failure until a reboot because the ESXi image actually runs in memory, so is only loaded from the USB stick at boot time.

The Solution
As for the solution, it’s really quite simple. I purchased a number of 12cm (5 inch) USB 2.0 extender cables on eBay for just 99p each (including delivery!).

These keep the USB stick indirectly attached to the NUC chassis, and as such the heat does not transfer into the flash drive. Since doing this I have not seen any further issues with the corruptions. Job done!

Keeping things cool: USB extender on Intel NUC

Keeping things cool: USB extender on Intel NUC

NanoLab – Part 8 – Quick Tip for Blank Screen on vPro Intel NUC

Just a very quick tip for an annoying issue I have experienced with my Intel NUC DC53427HYE and never quite found the time to look into it and find a proper fix, that is until a recent twitter conversation! Kudos and many thanks to Frank Brix Pedersen and Mads Fog Albrechtslund for finding the solution and an EU reseller, and Frank for testing and posting it on his blog site.

If you have a vPro NUC and dont connect it permanently to a screen, then when you next connect to it via the vPro remote KVM interface, you get nothing but a blank black screen.

Link to Franks post is here which explains the symptoms and fix in detail:
http://www.vfrank.org/2015/04/28/running-the-intel-nuc-headless-with-vmware-esxi/

Frank has the NUC5i5MYHE model, but the fault looks identical to the issue I have been seeing so I will be following his post and purchasing a Fit Headless dongle from Tiny Green PC for ÂŁ12 (and a rather ripoff ÂŁ12 postage cost unfortunately, but there don’t seem to be any other UK suppliers). It is also available from opencompany.dk for others in the EU.

I will update this post once I have tested it on the DC53427HYE!

 

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