To get wildcard supported certificates, we need to pass the challenge which requires adding TXT records in your dns records.
To get certificates for single domains, there is no need to modify dns records. Check this link https://micropyramid.com/blog/configure-ssl-with-letsencrypt-and-nginx/ for more info.

Containers run services in an isolated environment, if we deploy our applications using containers then the host system on which these containers are running will not be affected even though the applications running within containers are being hacked.

HTTP Authentication is used to allow access limit to a site or particular directories by validating the username and password. HTTP basic authentication can also be combined with other access restriction methods, for example, restricting access by IP address or by geographical location.

In this blog post, we will learn how to setup and use gitlab container registry to implement, test build and deploy your code automatically with Docker.

Data loss can happen when we accidentally delete the files, or when server crashes or system fails, or when we applied migrations to the data that didn't work so we don't get previous data with the schema. In the production environment, it's mandatory to do database backup when we do changes in the code.

Kubernetes manages containerized applications across multiple hosts. With years of experience in managing highly scalable products, google has released kubernetes an open source project which manages containerized applications across multiple hosts. Kubernetes is actively developed with more than 700 active developers. Kubernetes can be setup over any cloud platform any os. Its is based on etcd which is a key value store that provides shared configuration and service discovery for clusters.