Docker
type: "io.kestra.plugin.scripts.runner.docker.Docker"
Run a task in a Docker container.
This task runner executes tasks in a container-based Docker-compatible engine.
Use the containerImage
property to configure the image for the task.
To access the task's working directory, use the {{ workingDir }}
Pebble expression
or the WORKING_DIR
environment variable.
Input files and namespace files added to the task will be accessible from that directory.
To generate output files, we recommend using the outputFiles
task's property.
This allows you to explicitly define which files from the task's working directory
should be saved as output files.
Alternatively, when writing files in your task, you can leverage
the {{ outputDir }}
Pebble expression or the OUTPUT_DIR
environment variable.
All files written to that directory will be saved as output files automatically.
Examples
Execute a Shell command.
id: simple_shell_example
namespace: company.team
tasks:
- id: shell
type: io.kestra.plugin.scripts.shell.Commands
taskRunner:
type: io.kestra.plugin.scripts.runner.docker.Docker
commands:
- echo "Hello World"
Pass input files to the task, execute a Shell command, then retrieve output files.
id: shell_example_with_files
namespace: company.team
inputs:
- id: file
type: FILE
tasks:
- id: shell
type: io.kestra.plugin.scripts.shell.Commands
inputFiles:
data.txt: "{{ inputs.file }}"
outputFiles:
- "*.txt"
containerImage: centos
taskRunner:
type: io.kestra.plugin.scripts.runner.docker.Docker
commands:
- cp {{ workingDir }}/data.txt {{ workingDir }}/out.txt
Run a Python script in Docker and allocate a specific amount of memory.
id: allocate_memory_to_python_script
namespace: company.team
tasks:
- id: script
type: io.kestra.plugin.scripts.python.Script
taskRunner:
type: io.kestra.plugin.scripts.runner.docker.Docker
pullPolicy: IF_NOT_PRESENT
cpu:
cpus: 1
memory:
memory: "512Mb"
containerImage: ghcr.io/kestra-io/kestrapy:latest
script: |
from kestra import Kestra
data = dict(message="Hello from Kestra!")
Kestra.outputs(data)
Properties
delete
- Type: boolean
- Dynamic: ❌
- Required: ✔️
- Default:
true
Whether the container should be deleted upon completion.
fileHandlingStrategy
- Type: string
- Dynamic: ❌
- Required: ✔️
- Default:
VOLUME
- Possible Values:
MOUNT
VOLUME
File handling strategy.
How to handle local files (input files, output files, namespace files, ...). By default, we create a volume and copy the file into the volume bind path. Configuring it to
MOUNT
will mount the working directory instead.
config
- Type:
- string
- object
- Dynamic: ✔️
- Required: ❌
Docker configuration file.
Docker configuration file that can set access credentials to private container registries. Usually located in
~/.docker/config.json
.
cpu
- Type: Cpu
- Dynamic: ❌
- Required: ❌
Limits the CPU usage to a given maximum threshold value.
By default, each container’s access to the host machine’s CPU cycles is unlimited. You can set various constraints to limit a given container’s access to the host machine’s CPU cycles.
credentials
- Type: Credentials
- Dynamic: ✔️
- Required: ❌
deviceRequests
- Type: array
- SubType: DeviceRequest
- Dynamic: ❌
- Required: ❌
A list of device requests to be sent to device drivers.
entryPoint
- Type: array
- SubType: string
- Dynamic: ✔️
- Required: ❌
- Default:
[]
Docker entrypoint to use.
extraHosts
- Type: array
- SubType: string
- Dynamic: ✔️
- Required: ❌
Extra hostname mappings to the container network interface configuration.
host
- Type: string
- Dynamic: ✔️
- Required: ❌
Docker API URI.
memory
- Type: Memory
- Dynamic: ❌
- Required: ❌
Limits memory usage to a given maximum threshold value.
Docker can enforce hard memory limits, which allow the container to use no more than a given amount of user or system memory, or soft limits, which allow the container to use as much memory as it needs unless certain conditions are met, such as when the kernel detects low memory or contention on the host machine. Some of these options have different effects when used alone or when more than one option is set.
networkMode
- Type: string
- Dynamic: ✔️
- Required: ❌
Docker network mode to use e.g. host
, none
, etc.
pullPolicy
- Type: object
- Dynamic: ❓
- Required: ❌
shmSize
- Type: string
- Dynamic: ✔️
- Required: ❌
Size of /dev/shm
in bytes.
The size must be greater than 0. If omitted, the system uses 64MB.
user
- Type: string
- Dynamic: ✔️
- Required: ❌
User in the Docker container.
volumes
- Type: array
- SubType: string
- Dynamic: ✔️
- Required: ❌
List of volumes to mount.
Make sure to provide a map of a local path to a container path in the format:
/home/local/path:/app/container/path
. Volume mounts are disabled by default for security reasons — if you are sure you want to use them, enable that feature in the plugin configuration by settingvolume-enabled
totrue
.
Here is how you can add that setting to your kestra configuration:
kestra:
plugins:
configurations:
- type: io.kestra.plugin.scripts.runner.docker.Docker
values:
volume-enabled: true
Definitions
io.kestra.plugin.scripts.runner.docker.Cpu
Properties
cpus
- Type: integer
- Dynamic: ❌
- Required: ❌
The maximum amount of CPU resources a container can use.
Make sure to set that to a numeric value e.g.
cpus: "1.5"
orcpus: "4"
or For instance, if the host machine has two CPUs and you setcpus: "1.5"
, the container is guaranteed at most one and a half of the CPUs.
io.kestra.plugin.scripts.runner.docker.Memory
Properties
kernelMemory
- Type: string
- Dynamic: ✔️
- Required: ❌
The maximum amount of kernel memory the container can use.
The minimum allowed value is
4MB
. Because kernel memory cannot be swapped out, a container which is starved of kernel memory may block host machine resources, which can have side effects on the host machine and on other containers. See the kernel-memory docs for more details.
memory
- Type: string
- Dynamic: ✔️
- Required: ❌
The maximum amount of memory resources the container can use.
Make sure to use the format
number
+unit
(regardless of the case) without any spaces. The unit can be KB (kilobytes), MB (megabytes), GB (gigabytes), etc.
Given that it's case-insensitive, the following values are equivalent:
"512MB"
"512Mb"
"512mb"
"512000KB"
"0.5GB"
It is recommended that you allocate at least 6MB
.
memoryReservation
- Type: string
- Dynamic: ✔️
- Required: ❌
Allows you to specify a soft limit smaller than memory
which is activated when Docker detects contention or low memory on the host machine.
If you use
memoryReservation
, it must be set lower thanmemory
for it to take precedence. Because it is a soft limit, it does not guarantee that the container doesn’t exceed the limit.
memorySwap
- Type: string
- Dynamic: ✔️
- Required: ❌
The total amount of memory
and swap
that can be used by a container.
If
memory
andmemorySwap
are set to the same value, this prevents containers from using any swap. This is becausememorySwap
includes both the physical memory and swap space, whilememory
is only the amount of physical memory that can be used.
memorySwappiness
- Type: string
- Dynamic: ✔️
- Required: ❌
A setting which controls the likelihood of the kernel to swap memory pages.
By default, the host kernel can swap out a percentage of anonymous pages used by a container. You can set
memorySwappiness
to a value between 0 and 100 to tune this percentage.
oomKillDisable
- Type: boolean
- Dynamic: ❌
- Required: ❌
By default, if an out-of-memory (OOM) error occurs, the kernel kills processes in a container.
To change this behavior, use the
oomKillDisable
option. Only disable the OOM killer on containers where you have also set thememory
option. If thememory
flag is not set, the host can run out of memory, and the kernel may need to kill the host system’s processes to free the memory.
io.kestra.plugin.scripts.runner.docker.Credentials
Properties
auth
- Type: string
- Dynamic: ✔️
- Required: ❌
The registry authentication.
The
auth
field is a base64-encoded authentication string ofusername:password
or a token.
identityToken
- Type: string
- Dynamic: ✔️
- Required: ❌
The identity token.
password
- Type: string
- Dynamic: ✔️
- Required: ❌
The registry password.
registry
- Type: string
- Dynamic: ✔️
- Required: ❌
The registry URL.
If not defined, the registry will be extracted from the image name.
registryToken
- Type: string
- Dynamic: ✔️
- Required: ❌
The registry token.
username
- Type: string
- Dynamic: ✔️
- Required: ❌
The registry username.
io.kestra.plugin.scripts.runner.docker.DeviceRequest
Properties
capabilities
- Type: array
- SubType: array
- Dynamic: ❌
- Required: ❌
A list of capabilities; an OR list of AND lists of capabilities.
count
- Type: integer
- Dynamic: ❌
- Required: ❌
deviceIds
- Type: array
- SubType: string
- Dynamic: ✔️
- Required: ❌
driver
- Type: string
- Dynamic: ✔️
- Required: ❌
options
- Type: object
- SubType: string
- Dynamic: ❌
- Required: ❌
Driver-specific options, specified as key/value pairs.
These options are passed directly to the driver.
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