SMTP

Last night I was up until 6AM doing reboots and backups. It is not
unusual for NFS mount points to not mount or NIS to not bind after a reboot.  Those are bugs I am used to and always check for.

But postfix not starting is unusual, I didn’t check, didn’t notice,
went to sleep and so it didn’t get fixed until someone called around 2PM.

I’ll work on some sort of automated monitoring solution.

Server Reboots Friday 2AM-ish

     I will be rebooting the physical host machines Friday morning around 2AM.  This will affect most everything.  Downtime should be less than about 15 minutes if everything goes as planned.  This is to load new 5.4 kernels.

Web Server Upgrades

     I’ve upgraded the encryption suite on our web server to modern encryption.  An unfortunate side effect is that it will break compatibility with IE8 on WinXP and versions of Android 2.73 or earlier.

Tickless Kernels

     If you are running any Debian derived operating system, Ubuntu, Debian, Mint, Zorin, Julinux, etc, you may wish to try a tickless kernel.

     What tickless kernels do for you is eliminate the CPU from having to wake-up to service clock interrupts unless there is actual work to be done.  This saves a significant amount of CPU time on a single machine these days, particularly if Intel, because the overhead of context switching has increased significantly as the result of various CPU flaws that have to be worked around.

     This can significantly improve battery life in a laptop or tablet.

     Where this kernel really shines though is on the server side when hosting multiple virtual machines.  Each virtual machine has it’s own clock ticks wasting CPU, plus the host.  This can end up eating more CPU than the actual work the machines are doing.

     I have made available two kernels both based upon the recently released 5.4 final. One is called “client” and is intended for end user systems where interactive response and low latency are important.  This kernel is entirely preemptive.

     The second is called “server” and is for server loads like physical hosts hosting virtual machines, web servers, mail servers, etc.  It is the same as the client kernel except that it is non-preemptive.

     Both of these are based upon Ubuntu 19.10 configuration except modified to be completely tickless and modified to work on the i7-6850k / Asus z-190 systems.  The stock kernels do not talk to the network on these systems.  ALL CPUs and hardware supported by the Ubuntu kernels plus the above is supported by these.

     You can download these via ftp from ftp.eskimo.com:

        Login: anonymous

        Password: You@whereever.net (your e-mail address).

     Complaints, suggestions, questions can be sent to: nanook@eskimo.com

     After logging in cd /pub/kernel/linux-5.4-tickless/[client|server]

     Then prompt off

     mget *.deb

     After you’ve retrieved the files install with:

     dpkg -i *.deb

     These kernels aren’t signed.  Sorry but I’m not willing to buy in to the Microsoft Secure Boot extortion scheme, so you will need to have secure boot turned off to use these.

Fedora is now Rawhide

      Fedora.eskimo.com is now RawHide, a rolling release, rather than 29, 30, etc.  This means it’s always on the bleeding edge.  If you need a more stable Redhat based release I suggest Centos7.eskimo.com or Centos8.yellow-snow.net.

Guacamole

     Guacamole web access to shell server console and terminals is presently unavailable.

     Restoring the web server and then upgrading to 19.10 broke it to the point where it needs to be completely re-installed.  I am working on that.

     I apologize for the interruptions earlier but needed to fix various things so that the web server came up properly after a reboot.

Web Server

     Our web server is currently reverted to the software state it was in on October 24th.

     This is because a reboot was required after a software update this morning and upon rebooting it would not come back up.  It didn’t even provide the normal grub menu.

     I attempted to fix this with boot-repair but was unsuccessful.  So I saved the database, so at least we wouldn’t lose work you’ve done on your sites, and restored from backup.

     That too had problems although less severe and I was able to get the site operational.

     I am now in the process of upgrading Ubuntu, after which I’ll upgrade the website and then fix various things that broke.