Category Archives: linux

Stable Diffusion on cpu

Example image of cat
CPU Rendered Cat 512×512

AKA “Stable Diffusion without a GPU” 🙂

Currently, the ‘Use CPU if no CUDA device detected’ [1] pull request has not merged. Following the instructions at [2] and jumping down the dependency rabbit hole, I finally have Stable Diffusion running on an old dual XEON server.


Server specs:-
Fujitsu R290 Xeon Workstation
Dual Intel(R) Xeon(R) CPU E5-2670 @ 2.60GHz
SSD storage

Sample command line:-

time python3.8 scripts/ --prompt "AI image creation using CPU" --plms --ckpt sd-v1-4.ckpt --H 768 --W 512 --skip_grid --n_samples 1 --n_rows 1 --ddim_steps 50

Initial tests show the following:-

768 x 51250~1015
1024 x 76850~3024
1280 x 102450~6566
1536 x 128050OOMN/A
Resolution, Peak RAM and Time to Render

1) Typically only 18 (out of 32 cores) active regardless of render size.
2) As expected, the calculation is entirely CPU bound.
3) For an unknown reason, even with –n_samples and –n_rows of 1, two images were still created (time halved for single image in above table).

Another CPU Rendered Cat 512×512


It works. We gain resolution at the huge expense of memory and time.

AmigaOS4.1 (PPC) under FS-UAE and QEMU

I recently purchased AmigaOS 4.1 with a plan to familiarise myself with the OS via emulation before purchasing the Freescale QorIQ P1022 e500v2 ‘Tabor’ motherboard. In particular, I wanted to investigate the ssh and X display options, including AmiCygnix.

OS4.1 running under FS-UAE & QEMU, showing config and network status

However, despite being familiar with OS3.1 and FS-UAE I still managed to hit a few gotchas with the OS4 install and configuration.

Installation of the QEMU module was simple using the download and simple instructions from: In my case this was version 3.8.2qemu2.2.0 and installed in ~/Documents/FS-UAE/Plugins/QEMU-UAE/Linux/x86-64/ (your path may vary).

I then tried multiple FS-UAE configurations in order to get the emulated machine to boot with PPC, RTG and network support. A few options clash resulting in a purple screen on boot. Rather than work through the process from scratch, it’s easier to simply list my config here:-

accelerator = cyberstorm-ppc
amiga_model = A4000/OS4
gfx_card_flash_file = /home/snetting/Documents/FS-UAE/Kickstarts/picasso_iv_flash.rom
graphics_card = picasso-iv
graphics_memory = 131072
hard_drive_0 = /home/snetting/Amiga/SteveOS41.hdf
kickstart_file = Kickstart v3.1 rev 40.70 (1993)(Commodore)(A4000).rom
network_card = a2065
zorro_iii_memory = 524288

I used FS-UAE (and FS-UAE-Launcher) version 2.8.3.

Things to note:

  1. See for install advice regarding disk partitioning and FS type. This is important!
  2. Shared folders (between host OS and Emulation) are *not* currently supported when using PPC under FS-UAE. Post install, many additional packages were required, including network drivers which resulted in a catch-22 situation. I worked around this by installing a 3.1.4 instance and mounting both the OS4 and ‘shared’ drives here, copying the required files over then booting back into the OS4 PPC environment.
  3. For networking, UAE.bsdsocket.library in UAE should be disabled but the A2065 network card enabled. The correct driver from aminet is:
  4. The latest updates to OS4.1 (final) enable Zorro III RAM to be used in addition to accelerator RAM; essential for AmiCygnix. Once OS4.1 is installed and network configured, use the included update tool to pull OS4.1 FE updates.

The documentation at is definitely useful as a reference but don’t rely on it; it’s dated (2014) and not necessarily accurate.

Whilst I’ve written this from memory, I’ll happily recreate my install from scratch if anyone has any specific questions or issues.

Good luck!

ROMs are available from Cloanto:
OS4.1 and updates from Hyperion:

Building qtel (Echolink client) under Fedora Linux

With both my previous bad experience building qtel (the Linux EchoLink client) and recent discussions on a forum around similar difficulties – I thought I’d identify, resolve and document the issues.

I’m not sure what’s changed but the process is now very simple (Fedora 28):-

git clone
cd svxlink/
cd src
sudo dnf install cmake libsigc++20-devel qt-devel popt-devel libgcrypt-devel gsm-devel tcl-devel
cmake .

Depending on libs already installed, additional packages may be required – as indicated by failures during the ‘cmake’ stage.

GlusterFS / VG Metrics in Prometheus (OCP)

We had a requirement to gather LVM (VG) metrics via Prometheus to alert when GlusterFS is running low on ‘brick’ storage space. Currently, within Openshift 3.9 the only metrics seem to relate to mounted FS. A ‘heketi exporter module’ exists but this only reports space within allocated blocks. There doesn’t appear to be any method to pull metrics from the underlying storage.

We solved this by using a Prometheus pushgateway. Metrics are pushed from Gluster hosts using curl (via cron) and then pulled using a standard Prometheus scrape configuration (via prometheus configmap in OCP). Alerts are then pushed via alertmanager and eventually Cloudforms.

Import the pushgateway image:

oc import-image openshift/prom-pushgateway --from= --confirm

Create pod and expose route. Then, add scrape config to prometheus configmap:-

- job_name: openshift-pushgateway
scrape_interval: 30s
scrape_timeout: 30s
metrics_path: /metrics
scheme: http
- targets:

On GlusterFS hosts we then gather metrics in whatever way we like and push to the gateway via curl. Example:-

echo "VG_Gluster 42" | curl --data-binary @-"

The metrics are then visible via prometheus UI / Grafana and alerts via alertmanager and CFME respectively.

Dummy java loop/sleep for test of init scripts

A dummy java executable (actually a jar) was required to develop init scripts without access to the client’s application.   The process of creating a Java ‘sleep’ application and wrapping within a ‘jar’ complete with manifest was not obvious to me.  The ‘thread.sleep’ also didn’t work as I expected, requiring an additional exception handler.  Not to mention the requirement for the manifest to require multiple new lines before being syntactically correct (and no report otherwise when incorrectly parsed, except ‘no main manifest attribute’ when attempting to run).  Why Java, WHY?

The following tgz contains both the compiled java executable plus source, manifest and instructions to build / compile the jar should the wait time (default 100 seconds) need to be modified.

WaitLoop.tgz (source and executable tgz)
WaitLoop (Github Project)

The .jar can be executed with:-

java -jar WaitLoop.jar

X forwarding over ssh and sudo

This has bugged me for years – with random success depending on sudo, su – etc.

The proper solution:-

steve@studio:~$ ssh -X
Last login: Fri Feb 10 21:54:11 2017 from
[steve@fleabox ~]$ xauth list  MIT-MAGIC-COOKIE-1  b4339e07fb0e4febdde6128fc56419e4
[steve@fleabox ~]$ sudo su -
[sudo] password for steve: 
[root@fleabox ~]# xauth add  MIT-MAGIC-COOKIE-1  b4339e07fb0e4febdde6128fc56419e4
[root@fleabox ~]# virt-manager &
[1] 7168


Docker and Apache QuickStart

mkdir -p dockerfile/C7httpd; cd dockerfile/C7httpd
vi Dockerfile

FROM centos:7
MAINTAINER "Steve Netting"
ENV container docker
RUN yum -y --setopt=tsflags=nodocs update && \
yum -y --setopt=tsflags=nodocs install httpd && \
yum clean all


RUN chmod -v +x /

CMD ["/"]



# Make sure we're not confused by old, incompletely-shutdown httpd
# context after restarting the container. httpd won't start correctly
# if it thinks it is already running.
rm -rf /run/httpd/* /tmp/httpd*

exec /usr/sbin/apachectl -DFOREGROUND

docker build .
docker images
docker run -d -p:8082:80 steve/httpd:latest
docker ps
curl http://localhost:8082

... If you can read this page it means that this site is working properly ...

To start interactive shell from inside running container:
docker exec -i -t romantic_noyce /bin/bash

Retrieving SCSI/LUN IDs from Linux /dev/sd*

Useful to identify disks present before/after a rescan of LUNs:-

for x in `ls -1 /dev/sd*`; do echo -n "$x:"; sudo /sbin/scsi_id -g $x; done > file.txt

The output is then in the format:-


Capture output before/after rescan of SCSI bus then use something like this to reveal the newly added LUNs (SCSI IDs):-

sdiff prescan.txt postscan.txt | grep ">"  | awk '{ print $2 }' | cut -d":" -f2 | sort -n | uniq

VPN-like functionality over ssh tunnel (sshuttle)

Running TCP over TCP (for example, TCP over an SSH tunnel) results in poor performance and reliability.  There’s several ways to do this; for example basic port forwarding in ssh or via pppd over ssh.

However, there’s a much nicer solution:  sshuttle!

From GitHub:

“As far as I know, sshuttle is the only program that solves the following common case:

  • Your client machine (or router) is Linux, FreeBSD, or MacOS.
  • You have access to a remote network via ssh.
  • You don’t necessarily have admin access on the remote network.
  • The remote network has no VPN, or only stupid/complex VPN protocols (IPsec, PPTP, etc). Or maybe you are the admin and you just got frustrated with the awful state of VPN tools.
  • You don’t want to create an ssh port forward for every single host/port on the remote network.
  • You hate openssh’s port forwarding because it’s randomly slow and/or stupid.
  • You can’t use openssh’s PermitTunnel feature because it’s disabled by default on openssh servers; plus it does TCP-over-TCP, which has terrible performance (see below).”

‘sshuttle’ appears to be available in both in the standard debian/ubuntu repos and the RHEL/Centos EPEL repo.

The following creates ane then routes all traffic (including DNS lookuos) over a ‘VPN-like’ ssh tunnel.

sudo sshuttle --dns -r <user>@<target host>:<port> 0/0 -vv

Once this is working you can drop the -vv (verbose level 2).  Also, if you’re not concerned about DNS hijacking you can omit the –dns to speed up DNS lookups (resolve locally).  To stop the tunnel just CTRL-C.

The man page for sshuttle is quite detailed; check there for more information.