Missing Pods in a Kubernetes StatefulSet

I got an alert today about a pod being in CrashLoopBackOff... I went to investigate:

$ kubectl get pods -A
NAMESPACE         NAME                                                           READY   STATUS        RESTARTS         AGE
(truncated output)
default           webserver-0                                                    0/1     Running       2539 (23s ago)   6d13h
default           webserver-2                                                    1/1     Running       0                6d18h
default           webserver-3                                                    1/1     Running       0                6d18h
default           webserver-6                                                    1/1     Running       0                6d18h
default           webserver-7                                                    1/1     Running       0                6d18h
default           webserver-8                                                    1/1     Running       0                6d18h
default           webserver-9                                                    1/1     Running       0                6d18h

Notice the amount of restarts that webserver-0 has. And the fact that webserver-1 is missing...

I initially went the Windows way, trying to restart the statefulset:

$ kubectl rollout restart sts webserver
statefulset.apps/webserver restarted

... but this didn't solve the issue... Actually what's the issue?

Well, describing the pod showed that webserver-0 is trying to pull an older tag of the webserver image, 23.03, which isn't compatible with the version 23.04 which is running on all the other pods and microservices on the cluster... This causes it to fail the liveness probe and stay in this infinite loop:

$ kubectl describe pod webserver-0 | grep -i image
    Image:         artifact.host.fqdn/some/path/webserver:v23.03.26
  Normal   Pulled     25m                   kubelet                                Successfully pulled image "artifact.host.fqdn/some/path/webserver:v23.03.26" in 387.441222ms
  Normal   Pulling    24m (x2 over 25m)     kubelet                                Pulling image "artifact.host.fqdn/some/path/webserver:v23.03.26"
  Normal   Pulled     24m                   kubelet                                Successfully pulled image "artifact.host.fqdn/some/path/webserver:v23.03.26" in 314.222387ms

Interesting enough, all the other pods in the statefulset are running on webserver tag 23.04:

$ kubectl describe pod webserver-8 | grep -i image
    Image:          artifact.host.fqdn/some/path/webserver:v23.04.14

$ kubectl describe pod webserver-1 | grep -i image
Error from server (NotFound): pods "webserver-1" not found

$ kubectl describe pod webserver-9 | grep -i image
    Image:          artifact.host.fqdn/some/path/webserver:v23.04.14

The statefulset is OK with regards to the tag of the webserver image:

$ kubectl get sts webserver -o yaml | grep image
        image: artifact.host.fqdn/some/path/webserver:v23.04.14
        imagePullPolicy: Always

Let's look at the revision history:

$ kubectl rollout history sts webserver --revision 9 | grep -i image
    Image:      artifact.host.fqdn/some/path/webserver:v23.03.26

$ kubectl rollout history sts webserver --revision 10 | grep -i image
    Image:      artifact.host.fqdn/some/path/webserver:v23.04.14

$ kubectl rollout history sts webserver --revision 11 | grep -i image
    Image:      artifact.host.fqdn/some/path/webserver:v23.04.14

$ kubectl rollout undo sts webserver --to-revision 11
statefulset.apps/webserver skipped rollback (current template already matches revision 11)

Revision 10 was created by a helm upgrade command and 11 by my rolling restart...

Searching the internet got me to this interesting answer that says: The more likely event here seems like one of your node deletions took down pod-1 and pod-2 after pod-0 went unhealthy. In that case, we do not attempt to recreate pod-1 or 2 till pod-0 becomes healthy again. The rationale for …

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Kafka, Kubernetes and Not enough space

So I came across a situation and it took me a while to figure it out. So I'm putting this together as it might help others as well.

Let's say you have Bitnami's packaged Kafka cluster running on Kubernetes on StatefulSets, (so not managed by an operator like Strimzi). And the pods start restarting...

Looking at the logs you might see stuff like this:

-9ee616bdcf73, partition=0, highWatermark=0, lastStableOffset=0, logStartOffset=0, logEndOffset=0) with 1 segments in 2ms (32564/32564 loaded in /bitnami/kafka/data) (kafka.log.LogManager)
[2022-07-06 20:46:05,895] INFO Loaded 32564 logs in 161618ms. (kafka.log.LogManager)
[2022-07-06 20:46:05,896] INFO Starting log cleanup with a period of 300000 ms. (kafka.log.LogManager)
[2022-07-06 20:46:05,896] INFO Starting log flusher with a default period of 9223372036854775807 ms. (kafka.log.LogManager)
[2022-07-06 20:46:05,908] INFO Starting the log cleaner (kafka.log.LogCleaner)
[2022-07-06 20:46:05,999] INFO [kafka-log-cleaner-thread-0]: Starting (kafka.log.LogCleaner)
[2022-07-06 20:46:06,296] INFO [BrokerToControllerChannelManager broker=0 name=forwarding]: Starting (kafka.server.BrokerToControllerRequestThread)
[2022-07-06 20:46:06,419] INFO Updated connection-accept-rate max connection creation rate to 2147483647 (kafka.network.ConnectionQuotas)
[2022-07-06 20:46:06,428] INFO Awaiting socket connections on 0.0.0.0:9093. (kafka.network.Acceptor)
[2022-07-06 20:46:06,463] INFO [SocketServer listenerType=ZK_BROKER, nodeId=0] Created data-plane acceptor and processors for endpoint : ListenerName(INTERNAL) (kafka.network.SocketServer)
[2022-07-06 20:46:06,464] INFO Updated connection-accept-rate max connection creation rate to 2147483647 (kafka.network.ConnectionQuotas)
[2022-07-06 20:46:06,464] INFO Awaiting socket connections on 0.0.0.0:9092. (kafka.network.Acceptor)
[2022-07-06 20:46:06,473] INFO [SocketServer listenerType=ZK_BROKER, nodeId=0] Created data-plane acceptor and processors for endpoint : ListenerName(CLIENT) (kafka.network.SocketServer)
[2022-07-06 20:46:06,481] INFO [BrokerToControllerChannelManager broker=0 name=alterIsr]: Starting (kafka.server.BrokerToControllerRequestThread)
[2022-07-06 20:46:06,508] INFO [ExpirationReaper-0-Produce]: Starting (kafka.server.DelayedOperationPurgatory$ExpiredOperationReaper)
[2022-07-06 20:46:06,509] INFO [ExpirationReaper-0-Fetch]: Starting (kafka.server.DelayedOperationPurgatory$ExpiredOperationReaper)
[2022-07-06 20:46:06,511] INFO [ExpirationReaper-0-DeleteRecords]: Starting (kafka.server.DelayedOperationPurgatory$ExpiredOperationReaper)
[2022-07-06 20:46:06,512] INFO [ExpirationReaper-0-ElectLeader]: Starting (kafka.server.DelayedOperationPurgatory$ExpiredOperationReaper)
[2022-07-06 20:46:06,529] INFO [LogDirFailureHandler]: Starting (kafka.server.ReplicaManager$LogDirFailureHandler)
[2022-07-06 20:46:06,611] INFO Creating /brokers/ids/0 (is it secure? false) (kafka.zk.KafkaZkClient)
[2022-07-06 20:46:06,642] INFO Stat of the created znode at /brokers/ids/0 is: 511242113,511242113,1657140366624,1657140366624,1,0,0,72062637399277581,364,0,511242113
 (kafka.zk.KafkaZkClient)
[2022-07-06 20:46:06,643] INFO Registered broker 0 at path /brokers/ids/0 with addresses: INTERNAL://kafka-0.kafka-headless.default.svc.cluster.local:9093,CLIENT://kafka-0.kafka-headless.default.svc.cluster.local:9092, czxid (broker epoch): 511242113 (kafka.zk.KafkaZkClient)
[2022-07-06 20:46:06,758] INFO [ControllerEventThread controllerId=0] Starting (kafka.controller.ControllerEventManager$ControllerEventThread)
[2022-07-06 20:46:06,765] INFO …
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(K)Ubuntu 22.04 and Bluetooth Headphones

This article is somewhat an update of the one named Linux and Bluetooth Headphones. In that article I had tested on (K)Ubuntu 20.04, but this article is about version 22.04.

Just like in the above mentioned article, I recommend that you install and enable PipeWire. It is a lot easier to do in (K)Ubuntu 22.04. The TL;DR version would be:

First, check to see which audio server you're currently on. This command most probably will return 'pulseaudio':

$ pactl info | grep 'Server Name'
Server Name: pulseaudio

So... make sure you install PipeWire:

$ sudo apt update
$ sudo apt install pipewire
$ sudo apt install gstreamer1.0-pipewire libpipewire-0.3-{0,dev,modules} libspa-0.2-{bluetooth,dev,jack,modules} pipewire{,-{audio-client-libraries,pulse,bin,tests}}
$ sudo apt install wireplumber gir1.2-wp-0.4 libwireplumber-0.4-{0,dev}

Disable PulseAudio and enable PipeWire instead:

$ systemctl --user --now disable pulseaudio.{socket,service}
$ systemctl --user mask pulseaudio

$ sudo cp -vRa /usr/share/pipewire /etc/

$ systemctl --user --now enable pipewire{,-pulse}.{socket,service}

Now, you should see PipeWire in here:

$ pactl info | grep 'Server Name'
Server Name: PulseAudio (on PipeWire 0.3.48)

For even more details, read this excellent article.

I tested with EDIFIER NeoBuds Pro and not only that switching between A2DP and HSP/HFP works automagically but, more than that, LDAC codec also works (which previously only worked for SONY WH-1000XM3):

$ pactl list
(output omitted)
Card #5323
        Name: bluez_card.FC_E8_06_76_05_2C
        Driver: module-bluez5-device.c
        Owner Module: n/a
        Properties:
                api.bluez5.address = "FC:E8:06:76:05:2C"
                api.bluez5.class = "0x240404"
                api.bluez5.connection = "disconnected"
                api.bluez5.device = ""
                api.bluez5.icon = "audio-headset"
                api.bluez5.path = "/org/bluez/hci0/dev_FC_E8_06_76_05_2C"
                bluez5.auto-connect = "[ hfp_hf hsp_hs a2dp_sink ]"
                bluez5.profile = "off"
                device.alias = "EDIFIER NeoBuds Pro"
                device.api = "bluez5"
                device.bus = "bluetooth"
                device.description = "EDIFIER NeoBuds Pro"
                device.form_factor = "headset"
                device.name = "bluez_card.FC_E8_06_76_05_2C"
                device.string = "FC:E8:06:76:05:2C"
                media.class = "Audio/Device"
                factory.id = "14"
                client.id = "34"
                object.id = "132"
                object.serial = "5323"
        Profiles:
                off: Off (sinks: 0, sources: 0, priority: 0, available: yes)
                a2dp-sink: High Fidelity Playback (A2DP Sink) (sinks: 1, sources: 0, priority: 16, available: yes)
                headset-head-unit: Headset Head Unit (HSP/HFP) (sinks: 1, sources: 1, priority: 1, available: yes)
                a2dp-sink-sbc: High Fidelity Playback (A2DP Sink, codec SBC) (sinks: 1, sources: 0, priority: 18, available: yes)
                a2dp-sink-sbc_xq: High Fidelity Playback (A2DP Sink, codec SBC-XQ) (sinks: 1, sources: 0, priority: 17, available: yes)
                a2dp-sink-ldac: High Fidelity Playback (A2DP Sink, codec LDAC) (sinks: 1, sources: 0, priority: 19, available: yes)
                headset-head-unit-cvsd: Headset Head Unit (HSP/HFP, codec CVSD) (sinks: 1, sources: 1, priority: 2, available: yes)
                headset-head-unit-msbc: Headset Head Unit (HSP/HFP, codec mSBC) (sinks: 1, sources: 1, priority: 3, available: yes)
        Active Profile: a2dp-sink-ldac
        Ports:
                headset-input: Headset (type: Headset, priority: 0, latency offset: 0 usec, available)
                        Properties:
                                port.type = "headset"
                        Part of profile(s): headset-head-unit, headset-head-unit-cvsd, headset-head-unit-msbc
                headset-output: Headset (type: Headset, priority: 0, latency offset: 0 usec, available)
                        Properties:
                                port.type = "headset"
                        Part of profile(s): a2dp-sink, headset-head-unit, a2dp-sink-sbc, a2dp-sink-sbc_xq …
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Linux and Bluetooth Headphones

For newer versions of Linux, like (K)Ubuntu 22.04 (which have PipeWire already installed or even enabled by default), please go directly to (K)Ubuntu 22.04 and Bluetooth Headphones

Connecting a set of bluetooth headphones to your Linux computer is a simple thing, if you just want to listen to music. But what about when you want to use the microphone that is, most probably, embedded in those headphones?

How I tested?

All the below information was tested on Kubuntu 20.04 with the following headphones:

How to check if your microphone is working or not?

You can test from an application that makes use of the microphone like Skype or 8x8 Meet.

For example, in this screenshot, it doesn't work. Just go to https://8x8.vc/someRandomString and click the up arrow next to the microphone symbol to see the list of available microphones your computer has. You might see the headphones (in this particular example, the EDIFIER NeoBuds Pro are conected) but only the laptop's internal microphone is detected.

the mic doesn't show up

From the command line, you can run this command:

$ pactl list

At the end of the output, you should see something like this:

Card #31
  Name: bluez_card.FC_E8_06_76_05_2C
  Driver: module-bluez5-device.c
  Owner Module: 56
  Properties:
    device.description = "EDIFIER NeoBuds Pro"
    device.string = "FC:E8:06:76:05:2C"
    device.api = "bluez"
    device.class = "sound"
    device.bus = "bluetooth"
    device.form_factor = "headset"
    bluez.path = "/org/bluez/hci0/dev_FC_E8_06_76_05_2C"
    bluez.class = "0x240404"
    bluez.alias = "EDIFIER NeoBuds Pro"
    device.icon_name = "audio-headset-bluetooth"
    device.intended_roles = "phone"
  Profiles:
    a2dp_sink: High Fidelity Playback (A2DP Sink) (sinks: 1, sources: 0, priority: 40, available: yes)
    headset_head_unit: Headset Head Unit (HSP/HFP) (sinks: 1, sources: 1, priority: 30, available: no)
    off: Off (sinks: 0, sources: 0, priority: 0, available: yes)
  Active Profile: a2dp_sink
  Ports:
    headset-output: Headset (priority: 0, latency offset: 0 usec, available)
      Part of profile(s): a2dp_sink, headset_head_unit
    headset-input: Headset (priority: 0, latency offset: 0 usec, not available)
      Part of profile(s): headset_head_unit

Notice the Profiles section and the fact that the profile headset_head_unit is not available and, also, that the Active Profile is set to a2dp_sink.

The easy way: making HSP work

This only works for JBL TUNE205BT.

This is easy, as it doesn't require any hacks or additional software. Just edit the file /etc/pulse/default.pa and add auto_switch=2 to the line load-module module-bluetooth-discover. In the end, the file should look like this in that zone:

### Automatically load driver modules for Bluetooth hardware
.ifexists module-bluetooth-policy.so
#load-module module-bluetooth-policy
load-module module-bluetooth-policy auto_switch=2
.endif

Restart bluetooth and kill pulseaudio (it should respawn by itself):

$ sudo systemctl restart bluetooth
$ pulseaudio -k

Now, not only that the HSP profile will appear as available (notice the Profiles section and, also, the Active Profile)...

$ pactl list
Card #32
  Name: bluez_card.B8_F6_53_03_D4_1C
  Driver: module-bluez5-device.c
  Owner Module: 57
  Properties:
    device.description = "JBL TUNE205BT"
    device.string = "B8:F6:53:03:D4:1C"
    device.api = "bluez"
    device.class = "sound"
    device.bus = "bluetooth …
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ToXic Chat

ToXic Chat was a project I started in highschool (December of 2003) with Dragoș Bucevschi. The idea was to create a cross-platform (Windows and Linux), peer-to-peer (no dependency on a specific server), reliable (TCP) chat system.

Initial implementation was done in Delphi (Windows) and Kylix (Linux) and in 2005 I rewrote it in C++/Qt but I discontinued the project.

Version history:

  • 10th of May 2004 - 0.0.1
  • 23rd of May 2004 - 0.1.0
  • 30th of August 2004 - 0.2.0
  • 1st of September 2004 - 0.2.1
  • 16th of July 2005 - 0.4
  • 25th of December 2006 - 0.5 alpha1 - this was the version in C++/Qt but I discontinued the project.

The source code, binaries, installers and screenshots can be found on Sourceforge:

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QPdf2Swf

QPdf2Swf is a GUI (graphical user interface) written in Qt4 for pdf2swf, a pdf to swf converter. It was a demo that I wrote in a few hours for an interview at a company wanting to convert PDF presentation catalogs and render Flash pages from them. Flash websites were a thing in 2005 :)

I didn't get the job so I published the code online but didn't maintain it. You can view it on Sourceforge. It is cross platform and should run on both Windows and Linux (probably even Mac OS, but I didn't test)

Version history:

  • October 2005 - unreleased version, written in Qt 4.0
  • 31st of October 2006 - 0.1, the version I released, refactored in Qt 4.2
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