Aam S aamsur-mkt

Example

Use the df -h command to verify that the root partition mounted under "/" is full (100%). In the following example, /dev/nvme0n1p1 is using 100% of its space.

[ec2-user ~]$ df -h
Filesystem      Size  Used Avail Use% Mounted on
devtmpfs        460M     0  475M   0% /dev

Problem

[RedisException] MISCONF Redis is configured to save RDB snapshots, but is currently not able to persist on disk. Commands that may modify the data set are disabled. Please check Redis logs for details about the error.
On /var/log/redis/redis-server.log show # Can't save in background: fork: Cannot allocate memory

Explanation

This error occurs because of BGSAVE being failed. During BGSAVE, Redis forks a child process to save the data on disk. Although exact reason for failure of BGSAVE can be checked from logs (usually at /var/log/redis/redis-server.log on linux machines) but a lot of the times BGAVE fails because the fork can't allocate memory. Many times the fork fails to allocate memory (although the machine has enough RAM available) because of a conflicting optimization by the OS.

As can be read from Redis FAQ (https://redis.io/topics/faq):

Redis background saving schema relies on the copy-on-write semantic of fork in modern operating systems: Redis forks (creates a child process) t

Backup source
Delete db target
create db target
import source to target

pg_dump -U postgres -W -d example_backups > ~/Example_Dumps/ex_back_db.sql
DROP DATABASE example_backups_target;
CREATE DATABASE example_backups_target;
psql -U postgres -W -d example_backups_target -f ~/Example_Dumps/ex_back_db.sql

formula: https://api.github.com/repos/[user]/[reponame]/issues/[issue_id]/comments

example: https://api.github.com/repos/docker/compose/issues/1786/comments

then see the string value of body comment

Thanks @oelmekki for your insights. It has been very useful and encouraging when there is so few info on rolling updates with docker-compose.

I ended up writing the following script docker_update.sh <service_name>, which seems to work very decently. It relies on healthcheck command, which is not mandatory (change -f "health=healthy" accordingly) but cleaner IMHO than waiting for container to simply being up, when it takes a little time to boot (which will be the case if you run eg. npm install && npm start as a command).

#!/bin/bash

cd "$(dirname "$0")/.."

SERVICE_NAME=${1?"Usage: docker_update <SERVICE_NAME>"}

	# Optimized my.cnf configuration for MySQL/MariaSQL
	#
	# by Fotis Evangelou, developer of Engintron (engintron.com)
	#
	# ~ Updated January 2020 ~
	#
	#
	# The settings provided below are a starting point for a 2GB - 4GB RAM server with 2-4 CPU cores.
	# If you have different resources available you should adjust accordingly to save CPU, RAM & disk I/O usage.
	#

	sudo fallocate -l 2G /swapfile
	sudo chmod 600 /swapfile
	sudo mkswap /swapfile
	sudo swapon /swapfile
	sudo cp /etc/fstab /etc/fstab.bak
	echo '/swapfile none swap sw 0 0' \| sudo tee -a /etc/fstab
	sudo sysctl vm.swappiness=10
	sudo sysctl vm.vfs_cache_pressure=50
	echo 'vm.swappiness=10' \| sudo tee -a /etc/sysctl.conf
	echo 'vm.vfs_cache_pressure=50' \| sudo tee -a /etc/sysctl.conf

	<?php

	// regex untuk mencari static variable
	$re = "/(?s)'(?:[^'\\\\]\|\\\\.)'\|\"(?:[^\"\\\\]\|\\\\.)\"/";

	$str = file_get_contents($_GET['file']);

	preg_match_all($re, $str, $matches);
	if(count($matches) <= 0){
	return;

	#!/bin/bash

	#### Default Configuration

	CONCURRENCY=4
	REQUESTS=100
	ADDRESS="http://localhost:8080/"

	show_help() {
	cat << EOF

	## DEBIAN DOCKERFILE
	ENV TZ=Asia/Jakarta
	RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone

	## ALPINE DOCKERFILE
	RUN apk add --no-cache tzdata
	ENV TZ Asia/Jakarta

	## DEBIAN RUNNING CONTAINER
	export TZ=Asia/Jakarta && ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone