vault backup: 2025-04-18 20:58:54

17 files changed, 285 insertions, 49 deletions

diff --git a/.obsidian/workspace.json b/.obsidian/workspace.json
index d57c196..c2973af 100644
--- a/.obsidian/workspace.json
+++ b/.obsidian/workspace.json
@@ -4,86 +4,71 @@
     "type": "split",
     "children": [
       {
-        "id": "b5921b94f3580090",
+        "id": "f33c11cf18be28d7",
         "type": "tabs",
         "children": [
           {
-            "id": "8533accf5c2515ac",
+            "id": "3628dba7efa2e99a",
             "type": "leaf",
             "state": {
               "type": "markdown",
               "state": {
-                "file": "daily/11-Apr-2025.md",
+                "file": "Freenet CPU steal graph.md",
                 "mode": "source",
                 "backlinks": true,
                 "source": false
               },
               "icon": "lucide-file",
-              "title": "11-Apr-2025"
+              "title": "Freenet CPU steal graph"
             }
           },
           {
-            "id": "a06a83491e7620e5",
+            "id": "b1754e4cb810f3a0",
             "type": "leaf",
             "state": {
               "type": "markdown",
               "state": {
-                "file": "Device mapper.md",
+                "file": "How to show the mysql galera cluster status.md",
                 "mode": "source",
                 "backlinks": true,
                 "source": false
               },
               "icon": "lucide-file",
-              "title": "Device mapper"
+              "title": "How to show the mysql galera cluster status"
             }
           },
           {
-            "id": "30f6cf07a77bd478",
+            "id": "5ac5819f83e59327",
             "type": "leaf",
             "state": {
               "type": "markdown",
               "state": {
-                "file": "Examples of proper JQ usage.md",
+                "file": "Managing the amount of WSGI processes ran by apache is done from the apache site configuration.md",
                 "mode": "source",
                 "backlinks": true,
                 "source": false
               },
               "icon": "lucide-file",
-              "title": "Examples of proper JQ usage"
+              "title": "Managing the amount of WSGI processes ran by apache is done from the apache site configuration"
             }
           },
           {
-            "id": "c550cd183351059f",
+            "id": "487149710eacf558",
             "type": "leaf",
             "state": {
               "type": "markdown",
               "state": {
-                "file": "Using Libvirt to manage QEMU image bitmaps.md",
+                "file": "daily/18-Apr-2025.md",
                 "mode": "source",
                 "backlinks": true,
                 "source": false
               },
               "icon": "lucide-file",
-              "title": "Using Libvirt to manage QEMU image bitmaps"
-            }
-          },
-          {
-            "id": "5b6958c83833df4a",
-            "type": "leaf",
-            "state": {
-              "type": "markdown",
-              "state": {
-                "file": "daily/15-Apr-2025.md",
-                "mode": "source",
-                "backlinks": true,
-                "source": false
-              },
-              "icon": "lucide-file",
-              "title": "15-Apr-2025"
+              "title": "18-Apr-2025"
             }
           }
         ],
-        "currentTab": 4
+        "currentTab": 3
       }
     ],
     "direction": "vertical"
@@ -114,7 +99,7 @@
             "state": {
               "type": "search",
               "state": {
-                "query": "qemu bitm",
+                "query": "iptables",
                 "matchingCase": false,
                 "explainSearch": false,
                 "collapseAll": false,
@@ -234,12 +219,27 @@
       "obsidian-excalidraw-plugin:New drawing": false
     }
   },
-  "active": "5b6958c83833df4a",
+  "active": "487149710eacf558",
   "lastOpenFiles": [
-    "How to properly do options in a bash script with getopt!.md",
     "daily/15-Apr-2025.md",
-    "Using Libvirt to manage QEMU image bitmaps.md",
+    "daily/18-Apr-2025.md",
+    "Working with Nix shells.md",
+    "Managing the amount of WSGI processes ran by apache is done from the apache site configuration.md",
+    "How to show the mysql galera cluster status.md",
+    "Freenet CPU steal graph.md",
+    "daily/17-Apr-2025.md",
     "daily/14-Apr-2025.md",
+    "daily/16-Apr-2025.md",
+    "Debugging issues with updating Puppet dependency.md",
+    "It's recommended to use small-medium ARC for hypervisors where ZFS is used.md",
+    "How to RIP (grep).md",
+    "Using Libvirt to manage QEMU image bitmaps.md",
+    "Importing GPG keys from a keyserver.md",
+    "Exposing development headers on Nixos.md",
+    "About keyboard layout on Wayland.md",
+    "Benchmarking code in Golang.md",
+    "Testing Golang programs.md",
+    "How to properly do options in a bash script with getopt!.md",
     "We don't support filesystem discard syscalls on our openstack platform.md",
     "Examples of proper JQ usage.md",
     "Device mapper.md",
@@ -247,22 +247,7 @@
     "daily/10-Apr-2025.md",
     "List of tags I use in this Vault and their purpose.md",
     "Managing Ceph on Devstack & OpenStack.md",
-    "OpenStack Tempest.md",
-    "Tempest Plugin.md",
-    "High Gear Low Gear Testing.md",
-    "TDD.md",
-    "The volume type of a Cinder volume can be changed.md",
-    "How to (RIP) Grep.md",
-    "I assumed that Mohammed made an oopsie but instead it turned out to be one of us that forgot to clean up.md",
-    "Writing a test double before the real implementation gives feedback on design.md",
-    "London-style versus Detroit-style TDD.md",
-    "I'm worried that Freenet will completely go DOWN due to OVN upgrade.md",
-    "OVN upgrade.md",
     "daily",
-    "2025-04-10.md",
-    "Installing Ceph on devstack.md",
-    "Overview of Ceph.md",
-    "Gobs Ceph Client Key Access.md",
     "ESP",
     "Excalidraw"
   ]
diff --git a/.trash/Untitled 3.md b/.trash/Untitled 3.md
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/.trash/Untitled 3.md
diff --git a/About keyboard layout on Wayland.md b/About keyboard layout on Wayland.md
new file mode 100644
index 0000000..b4e8550
--- /dev/null
+++ b/About keyboard layout on Wayland.md
@@ -0,0 +1,15 @@
+---
+tags:
+  - wayland
+  - hyprland
+  - keyboard
+---
+In Wayland the keyboard layout is managed by the compositor. In my case that is currently Hyprland.
+
+To find variants:
+`localectl list-x11-keymap layouts:`
+`localectl list-x11-keymap-variants us`
+
+^ This doesn't seem to work on NixOS.
+
+I've set it now via `services.xserver.xkb.variant`, and queried variants from gemini.
\ No newline at end of file
diff --git a/Benchmarking code in Golang.md b/Benchmarking code in Golang.md
new file mode 100644
index 0000000..22d180d
--- /dev/null
+++ b/Benchmarking code in Golang.md
@@ -0,0 +1,40 @@
+---
+tags:
+  - golang
+  - howto
+---
+Simple timing can be done using the time package.
+```
+import time
+import fmt
+
+func main() {
+	start := time.Now()
+	elapsed = time.Since(start).Seconds()
+	fmt.Printf("%.2fs", elapsed)
+}
+```
+
+Writing benchmarks. They look similar to tests:
+```
+import testing
+
+func BenchmarkSome(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		Some()
+	}
+}
+```
+b.N is supplied by test driver and is dynamically changed depending on runtime.
+
+`go test -bench=<regex>`
+
+This just benchmarks a function being called many times, comparative benchmarks can be written using a regular function being called from Benchmarks, something like so :
+```
+import testing
+
+func doBench(b *testing.B, size int) { ... vary inputs size }
+func Bench1(b *testing.B)
+func Bench10(b *testing.B)
+func Bench100(b * testing.B)
+```
\ No newline at end of file
diff --git a/Debugging issues with updating Puppet dependency.md b/Debugging issues with updating Puppet dependency.md
new file mode 100644
index 0000000..da6e2f2
--- /dev/null
+++ b/Debugging issues with updating Puppet dependency.md
@@ -0,0 +1,46 @@
+---
+tags:
+  - puppet
+---
+Updated the ref in Puppetfile to yoga-eol instead of unmaintained/yoga.
+
+Stap 1: `librarian-puppet install --verbose`.
+Stap 2: `librarian-puppet update openstack-neutron --verbose`.
+
+Check puppet-neutron `metadata.json` This is where dependency information lives. According to the gitlab readme it is also possible that this lives in `Modulefile` or `Puppetfile`.
+
+Verbose info gives:
+```
+[Librarian] Failed to resolve puppetlabs-stdlib (>= 4.18.0, < 7.0.0) <(no source specified)> (from <nil>)
+```
+
+Erik determined this is due to `puppet-yum` by inspecting the lock file and checking who sets those requirements.
+```
+puppet master*​ ≡
+❯ rg '>= 4.18.0, < 7.0.0' Puppetfile.lock
+68:      puppetlabs-stdlib (>= 4.18.0, < 7.0.0)
+```
+```
+    1    │ puppet-yum (4.3.0)
+    1    │ │ puppetlabs-concat (>= 1.2.5, < 7.0.0)
+   68    │ │ puppetlabs-stdlib (>= 4.18.0, < 7.0.0)
+```
+
+It turns out that this version of `puppet-yum` came from `elastic-elastic_stack` which came in turn from `elastic-logstash`.
+We found that `elastic-logstash` has been deprecated, so we cannot upgrade this dependency. It is replaced by `puppet-logstash`.
+
+```
+puppet master ≡5s
+❯ rg puppet-yum Puppetfile.lock
+8:      puppet-yum (>= 0.9.6, < 5.0.0)
+66:    puppet-yum (4.3.0)
+
+hx Puppetfile.lock
+    elastic-elastic_stack (6.3.2)
+      puppet-yum (>= 0.9.6, < 5.0.0)
+
+```
+
+Changing the dependency from `elastic-logstash` to `puppet-logstash`, also brings issue.
+
+At the end our hacky resolution is to update the commit hash in `Puppetfile.lock` and push that. Possible only because we didn't change any dependencies in `openstack-neutron`.
diff --git a/Exposing development headers on Nixos.md b/Exposing development headers on Nixos.md
new file mode 100644
index 0000000..72db811
--- /dev/null
+++ b/Exposing development headers on Nixos.md
@@ -0,0 +1,15 @@
+---
+tags:
+  - nixos
+---
+On regular distro's such as Ubuntu we would install them system-wide, for example, `apt install libx`
+
+On NixOS these kind of outputs (on search.nixos.org the pkgs should specify out: dev) are not exposed by default, so installing the package system wide doesn't work.
+
+Instead they get loaded when the package is installed in a nix shell:
+```
+[nix-shell:~/projects/group.one/vps/openstack/puppet-neutron]$ cat shell.nix
+{ pkgs ? import <nixpkgs> {}}: pkgs.mkShell {
+  packages = [ pkgs.augeas pkgs.pkg-config pkgs.libxml2 ];
+}
+```
\ No newline at end of file
diff --git a/Freenet CPU steal graph.md b/Freenet CPU steal graph.md
index 1172c0b..b18c662 100644
--- a/Freenet CPU steal graph.md
+++ b/Freenet CPU steal graph.md
@@ -5,4 +5,4 @@ tags:
 ---
 `https://prometheus3.fnrz.de/graph?g0.expr=topk(5%2C%20avg_over_time(cpu_usage_steal%7Bcpu%3D%22cpu-total%22%7D%5B10m%5D))&g0.tab=0&g0.stacked=0&g0.show_exemplars=0&g0.range_input=12h`
 
-`sudo ip r a 194.97.212.67 via 172.16.16.1`
+`s i`
diff --git a/How to (RIP) Grep.md b/How to RIP (grep).md
index f7122a3..f7122a3 100644
--- a/How to (RIP) Grep.md
+++ b/How to RIP (grep).md
diff --git a/How to show the mysql galera cluster status.md b/How to show the mysql galera cluster status.md
new file mode 100644
index 0000000..27bb50f
--- /dev/null
+++ b/How to show the mysql galera cluster status.md
@@ -0,0 +1,14 @@
+---
+tags:
+  - mysql
+  - galera
+  - howto
+---
+Can be queried using `SHOW STATUS`.
+
+`sudo mysql --exec "SHOW STATUS LIKE 'wsrep%'"`
+
+**wsrep_cluster_status:**
+- Primary; desired state. Primary component (so the cluster is one big component). Quorum of nodes is present.
+- Non-Primary; Part of a partition (the non primary one) of nodes, so the cluster is partitioned. Cluster lost quorum.
+- Disconnected: The node is not connected to the cluster at all.
\ No newline at end of file
diff --git a/Importing GPG keys from a keyserver.md b/Importing GPG keys from a keyserver.md
new file mode 100644
index 0000000..d8981b2
--- /dev/null
+++ b/Importing GPG keys from a keyserver.md
@@ -0,0 +1,6 @@
+---
+tags:
+  - gpg
+  - howto
+---
+`gpg --keyserver <server> --recv-keys FINGERPRINT`
\ No newline at end of file
diff --git a/It's recommended to use small-medium ARC for hypervisors where ZFS is used.md b/It's recommended to use small-medium ARC for hypervisors where ZFS is used.md
new file mode 100644
index 0000000..a92d3d7
--- /dev/null
+++ b/It's recommended to use small-medium ARC for hypervisors where ZFS is used.md
@@ -0,0 +1,10 @@
+---
+tags:
+  - architecture
+  - nova
+  - zfs
+  - arc
+---
+https://papers.freebsd.org/2019/FOSDEM/jude-eli5_zfs_caching.files/ELI5_ZFS_ARC.pdf
+
+What is small-medium? TBD. For now we will go with the default of 1/32th of the total memory.
diff --git a/Managing the amount of WSGI processes ran by apache is done from the apache site configuration.md b/Managing the amount of WSGI processes ran by apache is done from the apache site configuration.md
new file mode 100644
index 0000000..6990073
--- /dev/null
+++ b/Managing the amount of WSGI processes ran by apache is done from the apache site configuration.md
@@ -0,0 +1,7 @@
+---
+tags:
+  - openstack
+  - wsgi
+  - apache
+---
+Instead of configuring for example `octavia.conf` the number of wsgi workers is controller via the httpd config at `/etc/apache2/sites-available/10-octavia_wsgi.conf`.[]()
\ No newline at end of file
diff --git a/Testing Golang programs.md b/Testing Golang programs.md
new file mode 100644
index 0000000..e9d48de
--- /dev/null
+++ b/Testing Golang programs.md
@@ -0,0 +1,9 @@
+---
+tags:
+  - golang
+  - howto
+---
+`go test` reads files ending with `_test.go`: 3 specialized functions:
+- Test functions; names start with Test, 1 arg. \*testing.T
+- Benchmarks: names start with Benchmarkt, 1 arg: \*testing.B
+- Example functions: names start with Example
\ No newline at end of file
diff --git a/Working with Nix shells.md b/Working with Nix shells.md
new file mode 100644
index 0000000..c042edd
--- /dev/null
+++ b/Working with Nix shells.md
@@ -0,0 +1,66 @@
+Basic invocation: `nix-shell -p [ pkgs ... ]`
+
+# Shebang
+```
+#! /usr/bin/env nix-shell
+#! nix-shell -i bash -p bash
+
+do stuff
+```
+
+Different interpreters can be set with the `-i` option such as python
+```
+#! /usr/bin/env nix-shell
+#! nix-shell -i python3 -p python3
+
+print("hello world")
+```
+
+The `-I` option can be used to pin nixpkgs
+```
+#! /usr/bin/env nix-shell
+#! nix-shell -i bash
+#! nix-shell -I nixpkgs=https://github.com/NixOS/nixpkgs/archive/aed4b19d312525ae7ca9bceb4e1efe3357d0e2eb.tar.gz
+
+echo hello world
+```
+# Shell.nix
+Can be used to set up per dir environments, e.g using direnv to automatically activate them.
+## Python
+https://nixos.org/manual/nixpkgs/stable/#python
+
+```nix
+{ pkgs ? import <nixpkgs> {}}:
+
+pkgs.mkShell {
+    packages = [ pkgs.virtualenv ];
+}
+```
+
+```nix
+with import <nixpkgs> {};
+let
+	my_toolz = python311.pkgs.buildPythonPackage rec { 
+		pname = "toolz";
+		version = "0.10.0";
+		pyproject = true;
+		src = fetchPypi {
+			inherit pname version;
+			hash = "sha256-CP3V73yWSArRHBLUct4hrNMjWZlvaaUlkpm1QP66RWA=";
+		};
+		nativeBuildInputs = [
+			python311.pkgs.setuptools
+			python311.pkgs.wheel
+		]; # has no tests
+		doCheck = false;
+		meta = {
+			homepage = "https://github.com/pytoolz/toolz/";
+			description = "List processing tools and functional utilities";
+			# [...]
+		};
+	};
+in python311.withPackages (ps: with ps; [ numpy my_toolz ]) ).env
+```
+
+					The [[Import]] is required here because imports a nix expression from another source, in this case nixpkgs.
+It is not required at line two, because python310Packages itself is already in the local scope.
\ No newline at end of file
diff --git a/daily/16-Apr-2025.md b/daily/16-Apr-2025.md
new file mode 100644
index 0000000..2d22b55
--- /dev/null
+++ b/daily/16-Apr-2025.md
@@ -0,0 +1,15 @@
+1op1 rutger: niet echt iets besproken.
+
+***Interview Prep Isabel***
+*Do you live in Amsterdam? If yes, how long? plans to stay?*
+
+*Very shortly worked for ING (2025 january until now). What happened?*
+
+*At Civir you mention "deployent & administration of cloud technologies" including openstack, does this mean you deplmoyed an openstack cloud or were you a user of an openstack deployment?*
+
+
+*You mention "24/7 support for troubleshooting issues" on multiple positions. What kind of issues?*
+
+***Isabel Q to us***
+
+**Isabel kwam niet opdagen**
\ No newline at end of file
diff --git a/daily/17-Apr-2025.md b/daily/17-Apr-2025.md
new file mode 100644
index 0000000..7a0a296
--- /dev/null
+++ b/daily/17-Apr-2025.md
@@ -0,0 +1,2 @@
+`puppet-neutron` gemerged; gezeik met updaten dependency, uiteindelijk commit hash in lock geupdate. Zie [[Debugging issues with updating Puppet dependency]].
+
diff --git a/daily/18-Apr-2025.md b/daily/18-Apr-2025.md
new file mode 100644
index 0000000..2b9620d
--- /dev/null
+++ b/daily/18-Apr-2025.md
@@ -0,0 +1,6 @@
+Encountered oom on lxchosts. Turned out that octavia wsgi was using huge amounts of ram. 
+First we disabled the apache on all octavia to prevent more oom kills.
+After that Erik limited their allowed memory usage, and we turned them back on.
+Found out that we can see what script is ran by apache in the vhost config. Turned out to be some CGI script.
+To profile the memory usage I stopped apache and ran a memory profiler directly against the cgi script, I had to stop the LB from using TLS but apart from that it worked smoothly.
+We now have a flamegraph of the memory usage, and it looks like it is something to do with ovs.
\ No newline at end of file