Docker Exec vs Attach and Docker wait Vs Docker Update

RajeshKumar1

Question 1: Docker Exec vs Attach

What is the difference between docker exec and docker attach when working with containers?
Give an example scenario where you would use each.

Question 2: Docker Wait vs Docker Update

Explain the difference between the docker wait and docker update commands.
When would you use docker wait, and when would you use docker update?

Kumar

RajeshKumar1

Question 1: Docker Exec vs Attach
What is the difference between docker exec and docker attach when working with containers?
Give an example scenario where you would use each.
Answer: docker exec is used to run commands in an running container.
docker attach is used to attach terminal to running container

Question 2: Docker Wait vs Docker Update
Explain the difference between the docker wait and docker update commands.
When would you use docker wait, and when would you use docker update?
Answer: docker update is used for updating the CPU resources, Increasing Memory like configuration changes. docker wait is used to stop the execution until container stops.

RifaquatullahKhan

ANS1: exec to run command on container using independent session
attach to run command on container using main process session
scenario: exec for running commands
attach to interact with container
ANS2: wait used to monitor container exit status
update used to modify running container settings

RajaS

Question 1: Docker Exec vs Attach
What is the difference between docker exec and docker attach when working with containers?
Docker Exec is used to execute any commands in the container. The command will be executed from working directory of container. This command executes in new process via interactive mode of running container
Docker attach will attach the I/O & error streams with primary process of running container.

Give an example scenario where you would use each.
Docker Exec can be used to check the version of Java or Apache in containers from terminal
docker exec containername java -version
Docker attach can be used when we need to monitor the logs / stats in a interactive mode

Question 2: Docker Wait vs Docker Update
Explain the difference between the docker wait and docker update commands.
Docker wait will be used to hold the execution of any process in the container till the container is stopped from different terminal. Usually used for any process to execute synchronously
Docker update is used to update the container settings / configuration without stopping or restarting the container. Usually used to configure settings for Memory, resources, etc. We can update the configurations online without impacting the process running in the container

When would you use docker wait, and when would you use docker update?
Docker wait can be used to perform automation, any scripts which needs synchronous execution, etc.
Docker update is used to configure CPO, Memory, Resource management settings online without impacting container

SantoshKumar

Docker Exec Vs Attach
Docker Exec is used to execute any command in the container. It doesnt disturn the main process PID.
Whereas Attach connects to the main process and exiting will kill the process as well. But we can exit
using CTRL+P, Q without stopping the process.

Docker Wait Vs Docker Update
Docker wait basicall would wait for the container to exit, when it exits, it will return exit code.
Docker Update allows us to change all the available configurations of container dynamically (runtime)

SanyaGarg

Question 1: Docker Exec vs Attach?
docker attach:

Connects to the running process inside the container (the process with PID 1).
Real-time monitoring of the container's output with respect to its input.
Ctrl+C while attached will terminate the main process and stop the container.
Example: use docker attach <container id> to monitor the logs of a web server running in a container.

docker exec:

Runs a new command or process inside the container, creating a new process.
Doesn't affect the main process of the container.
For running commands like bash for a shell, lets you start a new interactive shell session inside a running container.
Example: docker exec -it <container id> bash to get a shell inside the container for troubleshooting.

Question 2: Docker Wait vs Docker Update?
docker wait:

It is used to block (pause) your current terminal session until the specified containers stop. Once the container stops, the command returns their exit code.
Block until one or more containers stop, then print their exit codes.
Docker wait in automation scripts ensures that a container finishes its job before proceeding to the next step.
Example: docker wait will block until stops and then prints its exit code.
docker wait <container> (if output is 0, then sleep exited successfully)

docker update:

Docker update is used to modify the configuration settings of one or more running containers.
It allows you to change resource limits (like CPU and memory) or restart policies without stopping the containers.
Update resource allocation for critical containers to ensure consistent performance.
Example: To increase the CPU limit for container without stopping it.

ManuBhatnagar

What is the difference between docker exec and docker attach when working with containers?
Give an example scenario where you would use each.
Answer: Docker exec is used run a new process inside the container.
docker attach connects terminal to running container

Explain the difference between the docker wait and docker update commands.
When would you use docker wait, and when would you use docker update?

docker "wait" waits for a container to finish, where docker update is about modifying the running container like memory, cpou etc.

KhushiSinghania

ans 1 -
docker exec runs a new command in a running container.
docker attach connects your terminal to the container's main process
Example use case:
Use docker exec to run a one-off command, like docker exec -it my_container bash to open a shell.
Use docker attach to view logs or interact directly with the running container process

ans 2
docker wait blocks until the container stops and then returns its exit code.
docker update changes resource limits (like CPU or memory) of a running container.
When to use:
Use docker wait in scripts where you need to pause until a container finishes
Use docker update to adjust resource limits on the fly without restarting the container.

ArunSolairajan

Question 1: Docker Exec vs Attach
What is the difference between docker exec and docker attach when working with containers?
Give an example scenario where you would use each.

Docker attach command allows to attach the terminal to running container (existing process PID1)
Docker exec command allows to execute new commands in running container
Scenario:
Docker attach to interact with containers
Docker exec to execute commands

Question 2: Docker Wait vs Docker Update
Explain the difference between the docker wait and docker update commands.
When would you use docker wait, and when would you use docker update?

Docker wait command can be used for monitoring the container exit status by holding/blocking the execution of code/script.
Docker update command can be used to update the configurations of container which is running already
Scenario:
docker wait - to monitor, automation
docker update - memory configuration, cpu resources

likithadonta

Question 1: Docker Exec vs Attach
What is the difference between docker exec and docker attach when working with containers?
Give an example scenario where you would use each.

Docker exec is used to run or execute commands in a running container.

Use -You are running a web server in a container and want to inspect logs or install without affecting the server.

Docker attach connects the terminal to the main process of the container [pid 1]
Note: if we exit after attaching to container it stop the container because we it would be terminating the PID 1.
Trick: Ctrl+P then Crtl+Q to deattach without stopping the container.

Use - you started a container with a shell and want to reconnect it.

Question 2: Docker Wait vs Docker Update
Explain the difference between the docker wait and docker update commands.
When would you use docker wait, and when would you use docker update?

docker waits to pause the terminal the container stops, then prints its exit code
Use: when you are automating and to wait for a container to finish before running the next step.

docker update is used to modify resource (like cpu , memory ) for existing container.
Use: when you want ot change resource limits (lik --cpus=1)

likithadonta

Question 1: Docker Exec vs Attach
What is the difference between docker exec and docker attach when working with containers?
Give an example scenario where you would use each.

Docker exec is used to run or execute commands in a running container.

Use -You are running a web server in a container and want to inspect logs or install without affecting the server.

Use - you started a container with a shell and want to reconnect it.

Question 2: Docker Wait vs Docker Update
Explain the difference between the docker wait and docker update commands.
When would you use docker wait, and when would you use docker update?

docker waits to pause the terminal the container stops, then prints its exit code
Use: when you are automating and to wait for a container to finish before running the next step.

docker update is used to modify resource (like cpu , memory ) for existing container.
Use: when you want ot change resource limits (lik --cpus=1)

AshutoshBajpai

What is the difference between docker exec and docker attach when working with containers?
Give an example scenario where you would use each.

Docker exec is used to run a command in a container by not associating it with PID0 whereas docker attach is used to run a command in container by associating it to PID0

Docker exec scenario: Used when the command needs to be executed and control needs to be returned immediately
Docker attach scenario: Used when the command needs to be executed with in container with PID0

Explain the difference between the docker wait and docker update commands.
When would you use docker wait, and when would you use docker update?

docker wait is used to allow for gracefully wait on a container until it finishes with exit code whereas docker update is used to update the container configuration like cpu, memory etc.