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# Start a Scylla cluster
########################

docker run --name some-scylla -d scylladb/scylla --smp 1 --memory 750M --overprovisioned 1 --api-address 0.0.0.0
# Do not use the above --api-address for production. Exposing API IP is not secure.
SEED=$(docker inspect --format='{{ .NetworkSettings.IPAddress }}' some-scylla)
echo $SEED
docker run --name some-scylla2 -d scylladb/scylla --smp 1 --memory 750M --overprovisioned 1 --api-address 0.0.0.0 --seeds="$SEED"
docker run --name some-scylla3 -d scylladb/scylla --smp 1 --memory 750M --overprovisioned 1 --api-address 0.0.0.0 --seeds="$SEED"

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Measuring Firecracker boot time

Firecracker comes with an internal way of logging a timestamp that measures time elapsed between the very start of the guest VM and the moment a specific IO port has been written to.

That allows for marking specific moment along the boot process by having code writing to this port.

Artifacts build

Here we're going to measure the time it takes for a Firecracker guest VM to reach userspace. To do so we're going to build 3 components:

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How to update the Go version

System: Debian/Ubuntu/Fedora. Might work for others as well.

1. Uninstall the exisiting version

As mentioned here, to update a go version you will first need to uninstall the original version.

To uninstall, delete the /usr/local/go directory by:

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-- show running queries (pre 9.2)
SELECT procpid, age(clock_timestamp(), query_start), usename, current_query 
FROM pg_stat_activity 
WHERE current_query != '<IDLE>' AND current_query NOT ILIKE '%pg_stat_activity%' 
ORDER BY query_start desc;

-- show running queries (9.2)
SELECT pid, age(clock_timestamp(), query_start), usename, query 
FROM pg_stat_activity 
WHERE query != '<IDLE>' AND query NOT ILIKE '%pg_stat_activity%' 

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security and hardening options for systemd service units

A common and reliable pattern in service unit files is thus:

NoNewPrivileges=yes
PrivateTmp=yes
PrivateDevices=yes
DevicePolicy=closed
ProtectSystem=strict

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How to compile the linux kernel, launch it as a process and boot into Alpine linux

Command + Shift + 5

Host -> Docker GCC -> UML w/ Alpine 

# get docker for compiling
foo@host:~$ docker pull gcc
# launch new container
foo@host:~$ docker run --privileged --name gcc -it gcc /bin/bash

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// Basic Types
let id: number = 5
let company: string = 'Traversy Media'
let isPublished: boolean = true
let x: any = 'Hello'

let ids: number[] = [1, 2, 3, 4, 5]
let arr: any[] = [1, true, 'Hello']

// Tuple

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action_pool_depth
    Current value (from the default) = -1
      From //build/toolchain/BUILD.gn:10

    Pool for non goma tasks.

android_full_debug
    Current value (from the default) = false
      From //build/config/compiler/BUILD.gn:48

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Instructions how to install Debian using debootstrap. Below instructions were verified to work with debootstrapping Debian 11.

Table of contents

1. Conventions
2. Essential steps
   1. Install debootstrap
   2. Prepare disk for installing boot loader
      • BIOS systems

• GPT specific instructions

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• 0.1. References
• 0.2. Other cheatsheets
• 0.3. Manage multiple gcloud config configurations
  • 0.3.1. Switch gcloud context with gcloud config
• 0.4. Credentials
• 0.5. info
• 0.6. projects
• 0.7. zones & regions
• 0.8. Organization
• 0.9. billing