Thursday, 14 November 2019

Automatic Patch And Reboot on CentOS Server 6 7 or 8

CentOS seems to lack easy commands for automatically patching a server and then rebooting it if anything needs restarting.

Basically I want to run a script via /etc/cronttab at regular intervals to patch a system and reboot if necessary.  Obviously this might cause an outage (very rarely, some service won't restart), so we do it early in the morning, and we don't patch paired systems at the same time.

My script for Centos 6, 7 or 8 is attached below but it's a bit scrappy!   Does anyone have a better way?

Wednesday, 13 November 2019

HOWTO upload a Centos8 image to Digital Ocean


So you'd like to run Centos 8 on Digital Ocean... But the Cloud version of Centos 8 has not been released yet, so therefore Digital Ocean does not offer Centos 8 as an option...

No problem, just create a VM on your own workstation and then upload it as a Custom Image.

This HOWTO assumes you have a desktop running a Linux OS, with a copy of the free VMware Player installed.

Monday, 30 September 2019

Fixed: Saeco Intuita coffee machine - water coming from steam wand only

At the weekend I decided it was time to decalcify my coffee machine - a Saeco Intuita bean to cup machine that's served us well for 5 years.    I hadn't decalcified it for ages, and hadn't used the steam wand for months either.

After the cleaning cycle, I found the machine could not make coffee any more.  The brew unit seemed to be doing the rights things... Coffee beans were ground, and the little pucks of ground coffee were put into the waste hopper.  But water came out of the steam wand, and no coffee from the coffee spout.

The fix was to run some more cleaning cycles, and to use the hot water mode (press the tea cup button) to run lots of hot water through the steam wand.

I think the issue was that the decalcifying cycle must have disturbed some crud in the boiler, which then got stuck in the solenoid valve that controls the steam wand.  With that valve blocked open by the crud, the water was taking the easy route and coming out of the steam wand rather than going through the brew unit.

So.. if you get no coffee - just lots of water from the steam wand - your first step should be to set the machine to send hot water to the steam wand, and/or try one or two decalcifying cycles with or without decalcifying chemicals.

Tuesday, 30 April 2019

Fix: Windows 10 update stuck at 0% via HTTP Proxy

My new network requires my Windows 10 PC to sit behind an HTTP Proxy.  Normally this is no problem - the proxy settings configured in the browser just work - but sometimes the Windows Update process gets stuck at 0%.  Maybe there's a race condition.

Fix: 
      netsh winhttp set proxy proxy-server="1.2.3.4:3128"
from an elevated command prompt, where 1.2.3.4 is your Proxy server IP

Sunday, 14 April 2019

FIXED! MacOS 10.14.4 Update Breaks Gmail in Apple Mail

Like many Mac users, after taking an automatic update to 10.14.4 in early April 2019, my dad found that Apple Mail could no longer send or receive mail on a Google Mail account. 

The messsage "Google requires completing authentication in Safari" kept popping up when Mail was opened.  That took you to a Safari GMail login session - but that failed to work, even with the right password, so it went round and round in an endless loop...

I managed to fix it via the following steps:

Thursday, 14 February 2019

Fix for SSH login takes 90 seconds!

So...  We type:

ssh user@host.example.com

and it hangs for ages before it lets you log in.

On older distros, you got a delay of around 30 seconds unless you set UseDNS=No in /etc/ssh/sshd_config but that's the default on recent OS installs e.g. Ubuntu Server 18.04.

I had a different problem... The DNS for host.example.com had both A and AAAA records, and somehow IPv6 was taking precedence over IPv4 - despite my machine having no working IPv6 route.  This led to a login delay of around 90 seconds before it finally fell back to IPv4.

Fix: 

ssh -4 user@host.example.com

Duh'oh!

SCP the config from a Cisco ASA

The syntax you're looking for is:

scp user@myfirewall.myfqdn.com:system:running-config myfirewall.txt

Or indeed:

scp user@myfirewall.myfqdn.com:system:startup-config myfirewall.txt