SystemD System-V (init.d) compatibility layer and auto-restarts
SystemD (eg. RHEL7) has a compatibility layer for init.d services. When you run '/etc/init.d/ start', it doesn't do what you think it does; there is some magic involved. Have a look at the TurnKey...
View ArticleConfluent Schema Registry, cURL and Manipulating JSON with jq
Confluent Schema Registry, cURL and Manipulating JSON with jqIt's been a while since I last posted, but today I figured out how to do something useful.I've been deploying some Kafka recently, and today...
View ArticleClik here to view.
Deploying with Ansible when Outgoing Access to Internet is Unavailable (BYO...
So, you've completed your Dev environment in some nice throwaway VMs on your workstation (perhaps using Vagrant); your Ansible playbook is ready with a nice sheen to it, and your new shiny VMs are...
View ArticleClik here to view.
Laptop with small screen + Hyper-V + Install CentOS
So I've got a nice new Lenovo ThinkPad laptop for work. Its got lots of memory and disk, awesome battery life, and it's nice and portable; just the thing for a systems engineer -- it even has a wired...
View ArticleProvisioning Limited Access via Squid Proxy to Docker Containers
You have a Docker environment in your network; you limit outgoing traffic from your servers using a whitelisted proxy configuration (Squid) which can then be used for auditing. You wish to allow some...
View ArticleUsing Ansible to Fix CFEngine (after a trust failure as a result of...
One of the things I have been given (cursed with) in my life in IT is maintenance of CFEngine. CFEngine is one of the oldest, typically left on the wayside, systems for configuration management on...
View ArticleVirtualBox 5.1.27 + RHEL 7.4 (and others) + kernel update = suggest double...
For a long time now, every damn time I go to apply a kernel update, I have to rebuild the VirtualBox Guest Additions. If I have any vboxsf mounts set to mount at boot in /etc/fstab, I can look forward...
View ArticleVirtualBox 5.1.26 + RHEL 7.4 = GA 5.1.27 needed
Well, its that time of the month again when life gets difficult. That's right, it patching time. So naturally, on the Monday after patch week, I decided to apply the updates that VirtualBox was...
View ArticleVirtualBox 5.1.22 Guest Additions (un)install fail and fix
Patch time again, say goodbye to half a day with urgent Windows updates and routine VirtualBox / Linux etc. updates for my workstation.Anyway, it seems 5.1.22 fixed by earlier problem in 5.1.20 to do...
View ArticleVirtualBox 5.1.20 bug with Shared Folders (RHEL 7 guest)
Upgraded VirtualBox (as is my wont to do) and found the following problem after reinstalling the newer Guest Additions.I've submitted a bug report 16697 for this.# mount host_homemount: wrong fs type,...
View ArticleCapturing and Replaying Connection-less Protocols (eg. IPFIX into Logstash)
It can be useful to be able to capture AppFlow (IPFIX) data, which in our environment at least is UDP, and replay that on some other machine where you are playing with Logstash (or some other tool that...
View ArticleInstaller or command that hangs? Use /dev/urandom instead of /dev/random, but...
Okay, so I'm working on making an Ansible role for deploying an Oracle 10g Webgate, and I want it working on RHEL 6 and RHEL 7. I managed to do that (yay; took a bit of persuading), but quickly noticed...
View ArticleClik here to view.
[Humbledown highlights] VLAN tag stripping in Virtualbox (actually, Intel...
This is historical material from my old site, but as I have just bumped into a page that linked to it, I thought I would republish it. I have not verified that this material is still accurate.Feel free...
View ArticleMemcached logging (and others) under Systemd on RHEL7
I've been getting into RHEL7 lately (yay, a valid reason to get into at work!) and this means learning about systemd. This post is not about systemd... at least its not another systemd tutorial. This...
View ArticleUse IPTables NOTRACK to implement stateless rules and reduce packet loss.
I recently struck a performance problem with a high-volume Linux DNS server and found a very satisfying way to overcome it. This post is not about DNS specifically, but useful also to services with a...
View ArticleThe importance of being liberal in a Cisco environment
Okay, so today I grappled with a Cisco sized gorilla and won. -- me, earlier this year, apparently feeling rather chuffed with myself.I had recently launched a new service for a client, and a harvester...
View ArticleHow long has that command been running? (in seconds)
The ps command is fairly obtuse at the best of the times, but I am very thankful for things like ps -eo uid,command. I wish it were as easy to have ps report the starttime of a process in a form I can...
View ArticleClik here to view.
Answering 'Are we there yet?' in a Unix setting
Often -- commonly during an outage window -- you might get asked "How far through is that (insert-length-process-here)?". Such processes are common in outage windows; particularly unscheduled outages...
View ArticlePlease don't use dig etc. in reporting scripts... use 'getent hosts' instead...
Okay, so the excrement of the day is flying from the fan and you need to get some quick analytics of who/what is being the most-wanted of the day. Perhaps you don't currently the analytics you need at...
View ArticleMy Scriptorium on GitHub
I consider myself something of a toolsmith... when solving problems I often end up writing a script (or lengthy 'one-liner' more likely). Sometimes that script ends up being rather useful and I find...
View Article
