Security is a fundamental aspect of the deployment process. I ensure that credentials and sensitive data are encrypted and not hard-coded into scripts or configurations. Tools such as Vault or environment variables assist in managing this securely. Moreover, we implement role-based access controls (RBAC) to guarantee that only authorized personnel can initiate deployments or access production environments. For compliance, particularly in regulated industries, I establish audit trails to track changes made and their timing. Automated security scans, such as those using SonarQube or Snyk, are integrated into the CI/CD process to identify vulnerabilities before deployment. Rollbacks are a critical component of the CI/CD process. In TeamCity, I typically maintain a previous stable build that can be reverted to in case of failure. In Jenkins, I have set up automated rollback scripts that can be triggered if a deployment fails post-deployment tests or if monitoring tools detect issues. Keeping a clear version history in the repository is essential for both platforms, facilitating a straightforward rollback process with minimal downtime. Post-deployment testing involves automated regression tests, smoke tests, and performance tests. These tests are integrated into the pipeline to ensure that once the code is deployed, the system runs through them to verify functionality. Tools like Selenium for automated UI testing and JUnit for unit tests are often utilized. Additionally, I use monitoring tools to track application performance and to alert us to any issues arising after deployment.