When you use Logtail to collect logs from containers, you can use labels and environment variables to filter containers. Labels are included in container metadata that is returned by the docker inspect
command. Environment variables are runtime environment parameters that are configured to start containers. This topic describes how to obtain the labels and environment variables of a container.
Obtain labels
Log on to the host of the container whose labels you want to obtain. For more information about how to log on to an Elastic Compute Service (ECS) instance, see Connect to a Linux instance by using a password or key.
Run the following command to list all running containers:
docker ps
f******a
in the command output indicates the ID of the container.Emulate Docker CLI using podman. Create /etc/containers/nodocker to quiet msg. CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES f******a docker.io/library/nginx:latest nginx -g daemon o... 6 seconds ago Up 7 seconds 0.0.0.0:8080->80/tcp my-nginx
Run the following command to obtain the labels of the container:
docker inspect ${Container ID}
The
Labels
field in the command output indicates the labels of the container.
Obtain environment variables
Log on to the host of the container whose labels you want to obtain. For more information about how to log on to an Elastic Compute Service (ECS) instance, see Connect to a Linux instance by using a password or key.
Run the following command to list all running containers:
docker ps
f******a
in the command output indicates the ID of the container.Emulate Docker CLI using podman. Create /etc/containers/nodocker to quiet msg. CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES f******a docker.io/library/nginx:latest nginx -g daemon o... 6 seconds ago Up 7 seconds 0.0.0.0:8080->80/tcp my-nginx
Run the following command to obtain the environment variables of the container:
docker exec ${Container ID} env