Category Archives: Networking

dnsmasq: AWS – “Temporary failure in name resolution”, logs, debug and dnsmasq cache size

28 October 2019
 

 We are using AWS VPC DNS and sometimes facing with errors like “php_network_getaddresses: getaddrinfo failed: Temporary failure in name resolution“. The only advice from AWS tech. support was to configure a local dnsmasq service to act as a local DNS cache, but I did this already year ago and this issue happens once in 1-2-3… Read More »

OpenVPN: the No route to host and ERR_ADDRESS_UNREACHABLE errors – the cause and a solution

14 October 2019
 

 We have an OpenVPN Access Server running, see its setup in the OpenVPN: OpenVPN Access Server set up and AWS VPC peering configuration post. The VPN server is hosted in a first AWS VPC, while a Bitwarden service – in another one VPC. Between those VPCs we have a VPC peering configured, and the OpenVPN… Read More »

Redis: main configuration parameters and performance tuning overview

10 September 2019
 

 Currently configuring Redis server as our backend caching service and during that wrote this post with some things to pay attention at in Redis config file. Shortly enough but with links to other posts or documentation. Let’s begin with the redis-benchmark utility. Will be installed alongside with Redis service, so can be used right after… Read More »

Docker: Compose shared networks

20 August 2019
 

 We have a Docker Compose stack with Jenkins, SonarQube, and PostgresSQL, check the SonarQube: running tests from Jenkins Pipeline in Docker post. The problem is that they are described in the same Docker Compose file and are restarted by the same systemd file (check the Linux: systemd сервис для Docker Compose post, Rus) Thus, if… Read More »

Kubernetes: part 3 – AWS EKS overview and manual EKS cluster set up

15 August 2019
 

 Let’s proceed with our Kubernetes journey. Previous parts: Kubernetes: part 1 – architecture and main components overview Kubernetes: part 2 – a cluster set up on AWS with AWS cloud-provider and AWS LoadBalancer In this part we will start working with AWS Elastic Kuberneters Service (EKS) – its short overview, then will create Kubernetes Control… Read More »

Kubernetes: part 2 – a cluster set up on AWS with AWS cloud-provider and AWS LoadBalancer

10 August 2019
 

 In the first part – Kubernetes: part 1 – architecture and main components overview – we did a quick glance about Kubernetes. Also, check the third part – Kubernetes: part 3 – AWS EKS overview and manual EKS cluster set up. The next thing I’d like to play with is to manually create a cluster… Read More »

OpenVPN: Let’s Encrypt DNS verification on AWS Route53 and OpenVPN Access Server SSL certificate auto update

24 May 2019
 

 In addition to the OpenVPN: SSL and hostname configuration post about OpenVPN Access Server, set up and configuration. So, three months passed and it’s time to renew Let’s Encrypt SSL certificate (see. Prometheus: Alertmanager и blackbox-exporter — проверка срока действия SSL и нотификация в Slack, Rus). I could use a well-know for me scheme with… Read More »

AWS: VPC peering DNS resolution and DNS settings for OpenVPN Access Server

17 May 2019
 

 We have a VPC with OpenVPN Access Server running. This VPC is connected with other VPCs in our AWS account. The issue is that currently when a user is connected to VPN for the DNS resolution into EC2 instances private IPswe are using dnsmasq service on the VPN-host which has a /etc/dnsmasq.hosts file where are manually… Read More »

Redis: Sentinel – bind 0.0.0.0, the localhost issue and the announce-ip option

10 April 2019
 

 Originally, in a Sentinel’s configs, I have used the bind 0.0.0.0 to make them accessible from external hosts. Because of this when I started rolling out this setup on a real environment faced with an issue when Sentinels could not determine a Master host and other Sentinel hosts. In this post – such an issue… Read More »

Terraform: creating a project with an AWS EC2, VPC, and AWS cross-region VPC peering connection

18 March 2019
 

 One of the disappointing surprises in my AWS CloudFormation experience was the fact that it wasn’t able to automatically create cross-region VPC-peering connections. Note: this post originally was written in Rus on 28 June 2018 but now CloudFormation can do it, check the PeerRegion parameter of the AWS::EC2::VPCPeeringConnection resource. As a result – it tries… Read More »