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Using Rook+Ceph for persistent storage on Kubernetes
I wanted to install Prometheus and Grafana on my new Kubernetes cluster, but in order for these packages to work they need someplace to store persistent data. I had run performance and scale tests on...
View ArticleCreating AWS Elastic Filesystems (EFS) with Terraform
The AWS Elastic Filesystem (EFS) gives you an NFSv4-mountable file system with almost unlimited storage capacity. The filesystem I just created to write this article reports 9,007,199,254,739,968...
View ArticleRebooting a host with Ansible
For a long time rebooting a host with Ansible has been tricky. The steps are: ssh to the hostReboot the hostDisconnect before the host closes your ssh connectionWait some number of seconds to ensure...
View ArticleDetermine maximum MTU
I first started paying attention to network MTU settings when I was building petabyte-scale object storage systems. Tuning the network that backs your storage requires maximizing the size of the data...
View ArticleInstall a local .deb file and its dependencies
To install a local deb file and its dependencies use apt, not dpkg: sudo apt install ./foo-1.2.3.deb You’ll automatically get all of the dependencies installed with the package. (dpkg doesn’t...
View ArticleToo many authentication failures
I was working with a new Linux distro and after creating a brand-new VM with a single login I attempted to ssh into the VM only to be greeted with: Received disconnect from 10.0.0.180 port 22:2: Too...
View ArticleAutomatically decrypt multiple LUKS-encrypted volumes
I’ve written in the past on Adding an external encrypted drive with LVM to Ubuntu Linux and Adding a LUKS-encrypted iSCSI volume to Synology DS414 NAS but I neglected to mention how to automatically...
View ArticleHow to make the best drip-brewed coffee every time
My sister was visiting and I made a pot of coffee. My sister had a cup and said “That’s really good coffee. How did you make it?” I’ve gotten that same response from many, many people who drink my...
View ArticleFixing Docker pull timeout errors in Jenkins
Jenkins has a Docker plugin that allows you to authenticate with a docker image registry, pull the container image that you want, and then run tests inside the container. The plugin works well, and...
View ArticleMouse button Copy & Paste on Ubuntu 20.04
Using the left mouse button to select and copy text in terminals and the middle mouse button to paste has been a feature of X-Windows, and the various window managers built on top of X-Windows, since...
View ArticleGenerate a crypted password for Ansible
The Ansible user: command allows you to add a user to a Linux system with a password. The password must be passed to Ansible in a hashed password format using one of the hash formats supported by...
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Updating the vCenter appliance root password
If you’re like me, you rarely ssh into your vCenter appliance as “root”. However, the time comes when you need to update vCenter, you run the “Pre-Update Checks” — and because you never log into the...
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Upgrading vCenter 7 via the command line
I have vCenter 7.0.0.10700 installed and I want to update to 7.0.1.00200. When I run Update Planner > Interoperability it reports that all of my ESXi hosts are running ESXi 7.0.1. If I run the...
View ArticleGetting NVIDIA NGC containers to work with VMware PVRDMA networks
NVIDIA publishes a set of NVIDIA GPU-accelerated Containers (NGC) with applications and frameworks for machine learning, deep learning, and high-performance computing. VMware developed a platform that...
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Setting up a 100GbE PVRDMA Network on vCenter 7
After writing my last article on Getting NVIDIA NGC containers to work with VMware PVRDMA networks I had a couple of people ask me “How do I set up PVRDMA networking on vCenter?” These are the steps...
View ArticleFixing VSCode when it keeps dropping ssh connections
I really like VSCode, and I use the ssh plugin to edit code on remote machines, but recently the ssh connection has been dropping all of the time, even when I’m editing code on another machine that’s...
View ArticleAllow ping from specific subnets to AWS EC2 instances using Terraform
If you’re using Terraform to set up EC2 instances on AWS you may be a little confused about how to allow ping through the AWS VPC firewall, especially if you want to limit ping so that it only works...
View ArticleUpdating ESXi root passwords and authorized ssh keys with Ansible
I manage a number of vCenter instances and a lot of ESXi hosts. Some of the hosts are production, some for test and development. Sometimes an ESXi host needs to be used by a different group or...
View ArticleSetting up NFS FSID for multiple networks
The official documentation for creating an NFS /etc/exports file for multiple networks and FSIDs is unclear and confusing. Here’s what you need to know. If you need to specify multiple subnets that...
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Calculating the value for 64bitMMIOSizeGB
When adding a GPU to a vSphere VM using PCI passthrough there are a couple of additional settings that you need to make or your VM won’t boot. When creating the VM you’ll need to set the Actions >...
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