Method, device, and computer program product for managing image of container
In a method for managing an image of a container in a host device, a first image of a first container is received, wherein the first image includes a first set of image layers for implementing a first set of services of the first container respectively. The first image is loaded to deploy the first container at the host device. Based on an attribute of an image layer in the first set of image layers, an expiration time is set for the image layer. In response to determining that the expiration time is reached, the image layer is deleted from the host device. Stored image layers can be reused to reduce the transmission bandwidth for remotely downloading the image layers. A corresponding device and a corresponding computer program product are provided.
1. A method for managing an image of a container in a host device, comprising:
receiving a first image of a first container, the first image comprising a first set of image layers for implementing a first set of services of the first container respectively;
loading the first image to deploy the first container at the host device;
based on an attribute of an image layer in the first set of image layers, setting an expiration time for the image layer; and
in response to determining that the expiration time is reached, deleting the image layer from the host device;
wherein the attribute of the image layer comprises at least one of a parallel providing number of the image layer and a number of copies of the image layer in a host cluster; and
wherein the expiration time is determined at least in part as a function of the attribute of the image layer.
2. The method according to claim 1 , wherein setting an expiration time for the image layer comprises: setting the expiration time based on a level of the image layer, wherein the expiration time is inversely proportional to the level.
3. The method according to claim 1 , wherein setting an expiration time for the image layer comprises: setting the expiration time based on the parallel providing number of the image layer, wherein the expiration time is directly proportional to the parallel providing number, and the parallel providing number represents how many other host devices in the host cluster access the image layer in parallel at most.
4. The method according to claim 1 , wherein setting an expiration time for the image layer comprises: setting the expiration time based on the number of copies of the image layer in the host cluster, wherein the expiration time is inversely proportional to the number of the copies.
5. The method according to claim 1 , wherein setting an expiration time for the image layer comprises: setting the expiration time based on a difference between a current time and a time when the image layer was recently accessed, wherein the expiration time is inversely proportional to the difference, and the time when the image layer was recently accessed comprises at least one of the following:
a time when the host device recently accessed the image layer; and
a time when one or more other host devices in the host cluster recently accessed the image layer.
6. The method according to claim 1 , further comprising: in response to receiving an instruction to deploy a second container at the host device,
determining a second set of image layers for implementing a second set of services of the second container; and
in response to determining that a specified image layer in the second set of image layers is not in the host device, acquiring the specified image layer from one or more other host devices in the host cluster.
7. The method according to claim 6 , wherein acquiring the specified image layer from the one or more other host devices comprises:
acquiring a topological structure representing a connection between the host device and a plurality of other host devices in the host cluster; and
based on the topological structure, acquiring the specified image layer from the other host devices.
8. The method according to claim 6 , further comprising: in response to determining that the specified image layer is not in the host cluster, acquiring the specified image layer from an image server connected to the host cluster.
9. The method according to claim 1 , further comprising:
in response to receiving a request from one or more other host devices in the host cluster for acquiring the image layer, providing the image layer to the one or more other host devices; and
updating the expiration time of the image layer.
10. A method for managing an image of a container in a host device, comprising:
receiving a first image of a first container, the first image comprising a first set of image layers for implementing a first set of services of the first container respectively;
loading the first image to deploy the first container at the host device;
based on an attribute of an image layer in the first set of image layers, setting an expiration time for the image layer; and
in response to determining that the expiration time is reached, deleting the image layer from the host device;
wherein setting an expiration time for the image layer comprises: setting the expiration time based on a size of the image layer, wherein the expiration time is directly proportional to the size.
11. An electronic device, comprising:
at least one processor; and
a memory coupled to the at least one processor and having instructions stored therein, wherein the instructions, when executed by the at least one processor, cause the electronic device to perform actions for managing an image of a container in a host device, and the actions include:
receiving a first image of a first container, the first image comprising a first set of image layers for implementing a first set of services of the first container respectively;
loading the first image to deploy the first container at the host device;
based on an attribute of an image layer in the first set of image layers, setting an expiration time for the image layer; and
in response to determining that the expiration time is reached, deleting the image layer from the host device;
wherein the attribute of the image layer comprises at least one of a parallel providing number of the image layer and a number of copies of the image layer in a host cluster; and
wherein the expiration time is determined at least in part as a function of the attribute of the image layer.
12. The device according to claim 11 , wherein setting an expiration time for the image layer comprises: setting the expiration time based on a level of the image layer, wherein the expiration time is inversely proportional to the level.
13. The device according to claim 11 , wherein setting an expiration time for the image layer comprises: setting the expiration time based on the parallel providing number of the image layer, wherein the expiration time is directly proportional to the parallel providing number, and the parallel providing number represents how many other host devices in the host cluster access the image layer in parallel at most.
14. The device according to claim 11 , wherein setting an expiration time for the image layer comprises: setting the expiration time based on the number of copies of the image layer in the host cluster, wherein the expiration time is inversely proportional to the number of the copies.
15. The device according to claim 11 , wherein setting an expiration time for the image layer comprises: setting the expiration time based on a difference between a current time and a time when the image layer was recently accessed, wherein the expiration time is inversely proportional to the difference, and the time when the image layer was recently accessed comprises at least one of the following:
a time when the host device recently accessed the image layer; and
a time when one or more other host devices in the host cluster recently accessed the image layer.
16. The device according to claim 11 , wherein the actions further comprise: in response to receiving an instruction to deploy a second container at the host device,
determining a second set of image layers for implementing a second set of services of the second container; and
in response to determining that a specified image layer in the second set of image layers is not in the host device, acquiring the specified image layer from one or more other host devices in the host cluster.
17. The device according to claim 16 , wherein acquiring the specified image layer from the one or more other host devices comprises:
acquiring a topological structure representing a connection between the host device and a plurality of other host devices in the host cluster; and
based on the topological structure, acquiring the specified image layer from the other host devices.
18. The device according to claim 16 , wherein the actions further comprise: in response to determining that the specified image layer is not in the host cluster, acquiring the specified image layer from an image server connected to the host cluster.
19. An electronic device, comprising:
at least one processor; and
a memory coupled to the at least one processor and having instructions stored therein, wherein the instructions, when executed by the at least one processor, cause the electronic device to perform actions for managing an image of a container in a host device, and the actions include:
receiving a first image of a first container, the first image comprising a first set of image layers for implementing a first set of services of the first container respectively;
loading the first image to deploy the first container at the host device;
based on an attribute of an image layer in the first set of image layers, setting an expiration time for the image layer; and
in response to determining that the expiration time is reached, deleting the image layer from the host device;
wherein setting an expiration time for the image layer comprises: setting the expiration time based on a size of the image layer, wherein the expiration time is directly proportional to the size.
20. A computer program product tangibly stored on a non-transitory computer-readable medium and comprising machine-executable instructions, wherein the machine-executable instructions are used to implement a method for managing an image of a container in a host device, the method comprising:
receiving a first image of a first container, the first image comprising a first set of image layers for implementing a first set of services of the first container respectively;
loading the first image to deploy the first container at the host device;
based on an attribute of an image layer in the first set of image layers, setting an expiration time for the image layer; and
in response to determining that the expiration time is reached, deleting the image layer from the host device;
wherein the attribute of the image layer comprises at least one of a parallel providing number of the image layer and a number of copies of the image layer in a host cluster; and
wherein the expiration time is determined at least in part as a function of the attribute of the image layer.