• How to kill a docker swarm


    Assign way more replicas than you have of memory on all nodes and watch the Swarm crash which can easily reproduce in a small VMfor testing. root@Deb11Docker01:~# docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAM........
  • zfs and LUKS how to recover in Linux


    Sometimes users take their removal drives and unplug and replug them to test what happens during the failure of a disk. However, this breaks things quite badly due to the /dev/mapper in LUKS not coming back online due to it not being closed. In other words, generally with non-encrypted drives the process is smooth but when encrypted you may want to follow a strategy like this: We can see below that both disks are unavailable as they were physically remov........
  • Docker dockerd swarm high CPU usage cause solution


    If you have swarm services and dockerd is creating a high load even with the containers just being idle, the easiest solution is to upgrade to a newer docker version. For example an identical config of 3 nodes, with Redis 5 with 30 replicas produces a load of about 1.45 in Debian 10 with Docker18.09.1 If I create the same setup on Debian 11, with Docker 20.10.5+dfsg1 then the CPU usage is low. One other difference I wondered is the kernel. In my test setup........
  • GlusterFS HowTo Tutorial For Distributed Storage in Docker, Kubernetes, LXC, KVM, Proxmox


    This can be used on almost anything, since Gluster is a userspace tool, based on FUSE. This means that all Gluster appears as to any application is just a directory. Applications don't need specific support for Gluster, so long as you can tell the application to use a certain directory for storage. One application can be for redundant and scaled storage, including for within Docker and Kubernetes, LXC, Proxmox, OpenStack, etc or just your image/web/video files or even da........
  • Docker Tutorial HowTo Install Docker, Use and Create Docker Container Images Clustering Swarm Mode Monitoring Service Hosting Provider


    The Best Docker Tutorial for Beginners We quickly explain the basic Docker concepts and show you how to do the most common tasks from starting your first container, to making custom images, a Docker Swarm Cluster Tutorial, docker compose and Docker buildfiles.........
  • How to install Kubernetes with microk8s and deploy apps on Debian/Mint/Ubuntu Linux


    Kubernetes Easy Beginners Architecture Guide Kubernetes is known as container orchestration and we should start at explaining the container part of it. A Container is what runs the actual application and based on an Image, and are more comparable to something like an LXC Container, Virtuozzo/OpenVZ using the Linux Kernel Namespaces feature. Containers run these images as independent, isolated operating environments under the OS's exist........
  • CentOS 8 RHEL 8 Alma Linux Rocky Linux how to restart the network!


    Yes you have that right, the network service in RHEL8 / CentOS 8 / Rocky Linux / Alma Linux no longer exists. So there is no more systemctl restart network You can restart NetworkManager but it doesn't have the same effect or ifup/ifdown on all interfaces. Generally if NetworkManager is installed you will want to restart it or it won't apply the settings from ifcfg. systemctl restart NetworkManager To repl........
  • VMWare 6.7 VCSA VSphere ESXi Management SSO Install Guide on Linux using the CLI


    #mount the VCSA DVD mount /dev/sr0 /mnt/cd #alternatively you could mount the iso directly mount -o loop vcsa.iso /your/mount/path #for this purpose we are using the CLI installer on Linux cd /mnt/cd/vcsa-cli-installer/lin64 #no it's not going to be that easy you can't just run vcsa-deploy like that you need to use a template or configured .json file ./vcsa-deploy Usage: vcsa-deploy [-h] [--version] [--supported-deploymen........
  • Migrating from Linux Mint 17.2 mdadm RAID array to a new one (because I upgraded to larger drives).


    1.) Replicate the number of partitions in your new drives. gdisk /dev/sda gdisk /dev/sdb I created 3 partitions of the same same size. partition #1: +1G (/boot) partition #2: +60G (swap) partition #3: rest of it (/) #note if you are using GPT/gdisk you need to create separate a partition at least 1MB in size (in my case I would a 4th partition and mark it type ef02).........
  • ERROR 2013 (HY000): Lost connection to MySQL server during query


    The solution is simple but strange, if you copy your /var/lib/mysql directory to another server and think it will work, be sure to check if you have /var/log/mysql and binary log files. If you do, the server will not work and will give you errors like below and crash without the proper log files. UPDATE user SET password=password("newpass") WHERE user='root'; flush privileges; ERROR 2013 (HY000): Lost connection to MySQL server durin........
  • MySQL NEVER delete ib_logfile0 or ibdata1 or you'll lose data


    don't delete /var/lib/mysql/ib_logfile0 or ibdata1 or mysql won't restart I didn't realize they were internal and not part of replication like the relay files! /usr/libexec/mysqld: ready for connections. Version: '4.1.22-log' socket: '/var/lib/mysql/mysql.sock' port: 3306 Source distribution 110127 16:31:00 [Note] /usr/libexec/mysqld: Normal shutdown 110127 16:31:00 InnoDB: Starting shutdown...........
  • MySQL Replication/Dual-Master vs Clustering


    Many people aren't aware but recently Dual-Master Replication setups have become increasingly popular. That's because you get similar features and benefits of having a full-blown cluster (difficult to setup and maintain and requires I believe 3 servers just as controllers). With a dual-master you just have a different off-set for the keys and you should be good, but of course there is the chance that at some point replication will halt because of an unexpected or unforseen error........
  • mdadm RAID 1 adventures


    I separated the 2 drives in the RAID 1 array. 1 is the old one /dev/sda and is out of date, while the separated other one /dev/sdc was in another drive and mounted and used with more data (updated). I wonder how mdadm will handle this: usb-storage: device scan complete md: md127 stopped. md: bind md: md127: raid array is not clean -- starting background reconstruction raid1: raid set md127 active with 1 out of 2 m........
  • Basic Port Listing


    Basic Port ListingHopefully someone finds this useful or at least interesting. http://www.sans.org/top20/#u9 Name Port Protocol Description Small services ........
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