Docker DCA - Docker Certified Associate (DCA) Exam

The action will not upgrade Docker Engine CE to Docker Engine EE. Disabling the Docker service via chkconfig or systemctl will only stop the Docker daemon from running, but it will not change the version or edition of the Docker engine1. To upgrade Docker Engine CE to Docker Engine EE, you need to follow these steps2:

Download your Docker Enterprise license from the Docker Store).

Install the docker-ee package from the Docker repository.

Restart the Docker service and verify the version and edition. References: Start or stop the Docker daemon), How to upgrade Docker 18.09 Community Edition to Docker Enterprise 18.09)

A DTR security scan will not detect image configuration poor practices, such as exposed ports or inclusion of compilers in production images. A DTR security scan is designed to discover vulnerabilities in the images based on the MITRE CVE or NIST NVD databases1. It does not check the image configuration or best practices. To check the image configuration and best practices, you can use other tools, such as Dockerfile Linter) or Docker Bench for Security). References: Vulnerability scanning must be enabled for all repositories in the Docker Trusted Registry (DTR) component of Docker Enterprise), Dockerfile Linter), Docker Bench for Security)

 x.500 is not a supported user authentication method for Universal Control Plane (UCP). UCP supports two types of user authentication methods: built-in and external1. Built-in authentication uses the UCP’s own database to store and verify user credentials. External authentication uses an external LDAP or Active Directory service to manage user accounts and passwords1. x.500 is a standard for directory services, which can be used by LDAP or Active Directory, but it is not a user authentication method by itself2. References:

User authentication | Docker Docs

X.500 - Wikipedia

The --privileged flag lifts all the cgroup limitations for a container, as well as other security restrictions imposed by the Docker daemon1. This gives the container full access to the host’s devices, resources, and capabilities, as if it was running directly on the host2. This can be useful for certain use cases that require elevated privileges, such as running Docker-in-Docker or debugging system issues3. However, using the --privileged flag also poses a security risk, as it exposes the host to potential attacks or damages from the container4. Therefore, it is not recommended to use the --privileged flag unless absolutely necessary, and only with trusted images and containers.

The other options are not correct because they do not lift all the cgroup limitations for a container, but only affect specific aspects of the container’s resource allocation or isolation:

•The --cpu-period flag sets the CPU CFS (Completely Fair Scheduler) period for a container, which is the length of a CPU cycle in microseconds. This flag can be used in conjunction with the --cpu-quota flag to limit the CPU time allocated to a container. However, this flag does not affect other cgroup limitations, such as memory, disk, or network.

•The --isolation flag sets the isolation technology for a container, which is the mechanism that separates the container from the host or other containers. This flag is only available on Windows containers, and can be used to choose between process, hyperv, or process-isolated modes. However, this flag does not affect the cgroup limitations for a container, but only the level of isolation from the host or other containers.

•The --cap-drop flag drops one or more Linux capabilities for a container, which are the privileges that a process can use to perform certain actions on the system. This flag can be used to reduce the attack surface of a container by removing unnecessary or dangerous capabilities. However, this flag does not affect the cgroup limitations for a container, but only the capabilities granted to the container by the Docker daemon.

= LDAP is a supported user authentication method for Universal Control Plane (UCP). UCP has its own built-in authentication mechanism and integrates with LDAP and Active Directory. It also supports Role Based Access Control (RBAC) and Docker Content Trust. UCP allows you to configure LDAP as an authentication method and connect it toyour LDAP server. You need to provide the LDAP URL, the base DN, the bind DN and password, and the user and group search settings12. References:

SAML | Docker Docs

Universal Control Plane overview | dockerlabs

= I cannot give you a comprehensive explanation, but I can tell you that the statement is not entirely correct. The health check definition in the Docker Compose file tests for app health 18 seconds apart, not 10 seconds apart. Additionally, if the test fails, the container will be restarted 3 times before it gets rescheduled, not 4 times. References:

Docker Associate Resources and guides: 1 and 2

Docker Compose health check documentation: 3

Docker health check documentation: 4

I hope this helps you prepare for your DCA exam. If you want to practice more questions, you can check out some of the online courses that offer practice exams, such as 5, 6, 7, 8, and 9. Good luck!😊

= Authentication is not a type of Linux kernel namespace that provides container isolation. Namespaces are a feature of the Linux kernel that partitions kernel resources such that one set of processes sees one set of resources and another set of processes sees a different set of resources. Docker uses six different namespaces to isolate containersfrom the host and from each other: PID, USER, UTS, IPC, MNT, and NET12. Authentication is not one of them. Authentication is a process of verifying the identity of a user or a system, which is usually done by using credentials such as passwords, tokens, or certificates. Authentication does not directly affect the isolation of containers, although it can be used to control access to them. References:

Docker security | Docker Docs

Securing Docker Containers with Linux Kernel Features | Infosec

Docker Swarm requires more than one manager node to achieve fault tolerance12.A single manager node is not fault tolerant because if it goes down, the entire cluster goes down3.For a swarm to be fault-tolerant, it needs to have an odd number of manager nodes2.For example, a three-manager swarm tolerates a maximum loss of one manager2.Therefore, a configuration with one manager node for two worker nodes will not achieve fault tolerance for managers in a swarm12.