While deploying the playbook the below error appears:
ERROR! variable files must contain either a dictionary of variables, or a list of dictionaries. Got: user_password:password database_password:password ( <class ‘ansible.parsing.yaml.objects.AnsibleUnicode’>)
Dictionary file
ansible vault variables
In order to resolve issue, you should just leave a blank between dictionary key and value.
Deploy again your playbook and the result will be successful.
Ansible is a very powerful automation tool that is developed from RedHat. Many large organizations rely on Ansible to automate tasks and procedures. In this article I will explain how one can use ansible to manage windows clients and servers.
In order to manage windows hosts ansible winrm plugin should be used to communicate with the client/server machine.
The first step is to verify that ansible is installed.
Alongside with ansible, on the control node the pywinrm module should be also installed. By default this one is not installed and one should do it manually.
The managed Windows client/server machines should be configured to allow remote connections. A very useful power shell script is already developed from other users and it needs only to be executed on the managed host.
If your execution policy is prohibiting this script to be executed, you should set-execution policy to RemoteSigned as shown below and then execute the powershell.
Control node should have network connectivity with the managed hosts.
Some environmental variables should be used, so that ansible knows how the connection will be performed (winrm). I included those variables in my inventory file as I created this lab just for demonstration. My inventory file looks like below:
Lastly make sure that the user that is used for the connection has administrative rights on the managed windows hosts. Otherwise some error codes will be returned.
Lastly confirm ansible on managed host is working by using win_ping module.
Availability is a critical matter when it refers to systems. The ideal scenario for an administrator would be 100% availability for a virtual server/appliance.
However this is not achievable when we deal with infrastructure as we need to close the systems on purpose (patching, maintenance tasks, etc) but also disasters or other nonphysical causes create a downtime.
When we deal with Azure cloud we have the following options that we can use:
Availability sets
Availability zone
An Availability Zone is a high-availability offering that protects your applications and data from datacenter failures. Availability Zones are unique physical locations within an Azure region. Each zone is made up of one or more datacenters equipped with independent power, cooling, and networking. To ensure resiliency, there’s a minimum of three separate zones in all enabled regions
Availability sets are another datacenter configuration to provide VM redundancy and availability. This configuration within a datacenter ensures that during either a planned or unplanned maintenance event, at least one virtual machine is available and meets the 99.95% Azure SLA. For more information, see the SLA for Virtual Machines.
When you create a new VM resource on Azure, you should choose between availability sets or availability zone (depending on the region on which you deployed your server)
However as stated in the first article from Microsoft:
To achieve comprehensive business continuity on Azure, build your application architecture using the combination of Availability Zones with Azure region pairs. You can synchronously replicate your applications and data using Availability Zones within an Azure region for high-availability and asynchronously replicate across Azure regions for disaster recovery protection.
So the final image is the below. Based on your needs you could choose whichever option is more appropriate for you. However as recommended from Microsoft, you should use availability zones (newer feature than availability sets)
Below are some very good resources that Microsoft provides:
In this article I will explain a HAproxy installation on docker centos images. First things first, 3 centos images should be deployed. Two of them will be simple web servers with httpd installed and the third one will have haproxy installed to load balance between the two web servers.
In order to deploy 3 new centos docker images you should first download the latest centos image.
Just pull the Centos docker image from dockerHub by using the below command
docker pull centos
And then deploy 3 instances of it:
docker container run -it --name centos-lab1 -d centos:latest
docker container run -it --name centos-lab2 -d centos:latest
docker container run -it --name centos-lab3 -d centos:latest
Verify that containers have been deployed succesfully and execute some interactive commands on them.
docker exec -it centos-lab1 uname -r
You will get a result like the below, depending on the image you have installed.
4.19.76-linuxkit
Install httpd package on the two web servers. I am using portainer so that I can interact easier with containers. You could also execute an interactive command as shown below.
yum install httpd
docker exec -it centos-lab2 yum install httpd
Lastly you should install haproxy package for the third server that will be used as a load balancer.
Verify connectivity between your containers. Based on the default network that have been deployed on my computer I get the following 3 IP’s.
172.17.0.4 , 172.17.0.5 , 172.17.0.6
Install a test html page on web servers that will be used to identify the node.
echo "this is centos-lab1" > /var/www/html/index.html
echo "this is centos-lab2" > /var/www/html/index.html
Enable and start httpd server on web servers and test that their page is up and running by running a curl from load balancer (server 3). You will get a respond like the below:
apache is running and responding on web servers 1,2
