• Monitoring the progress of dd

    2 min read

    For a long time we were not able to properly monitor the progress of a dd command unless we were using pv of having another process to periodically send a SIGUSR1 to the dd process

    17/09/2021

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  • Using nmap to brute-force SSH

    2 min read

    If we have a bunch of Raspberries on our network and we want to make sure we are not using the default password on any of them, we can using nmap fo trying to brute-force into them

    15/09/2021

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  • unable to retrieve the complete list of server APIs

    2 min read

    While performing any action we might encounter the following error:

    error: unable to retrieve the complete list of server APIs: metrics.k8s.io/v1beta1: the server is currently unable to handle the request
    

    03/05/2021

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  • Troubleshoot Kubernetes service not being resolved

    2 min read

    When you create a Kubernetes Service, pods from within the same namespace should be able to resolve it's IP by name. For example, if we create a service named ampa-votacions; any pod from the same namespace should be able to resolve it's IP. But sometimes it can't be resolved:

    $ kubectl exec -it ampa-install-ws7cw -- sh
    / $ nslookup ampa-votacions
    Server:   172.20.0.10
    Address:  172.20.0.10:53
    
    ** server can't find ampa-votacions.us-west-2.compute.internal: NXDOMAIN
    
    ** server can't find ampa-votacions.ampa.svc.cluster.local: NXDOMAIN
    
    ** server can't find ampa-votacions.svc.cluster.local: NXDOMAIN
    
    ** server can't find ampa-votacions.ampa.svc.cluster.local: NXDOMAIN
    
    ** server can't find ampa-votacions.cluster.local: NXDOMAIN
    
    ** server can't find ampa-votacions.svc.cluster.local: NXDOMAIN
    
    ** server can't find ampa-votacions.cluster.local: NXDOMAIN
    
    ** server can't find ampa-votacions.us-west-2.compute.internal: NXDOMAIN
    

    19/04/2021

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  • JVM heap options: Xmx and Xms

    2 min read

    The Xmx and Xms settings are most commonly overlooked settings but yet quite critical for the JVM to perform as expected. They control the JVM's heap: the memory area where objects are instantiated.

    15/04/2021

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From pet to cattle
Treat your kubernetes clusters like cattle, not pets