Copying Container Images

Abstract

Container images can be copied. For example, a computing device can segment a container image into at least two data chunks. The computing device can determine a reference count for a data chunk among the at least two data chunks. The computing device can determine that the reference count for the data chunk is below a threshold value. In response to determining that the reference count for the data chunk is below the threshold value, the computing device can prevent a destination device from being queried about the data chunk prior to transmitting the data chunk to the destination device.

1 . A system comprising:
 a processing device; and   a memory device including instructions that are executable by the processing device for causing the processing device to:
 receive a request for a container image from a client device; and 
 in response to receiving the request:
 determine a reference count for a data chunk among at least two data chunks of the container image, the reference count indicating how many times the data chunk is present in a plurality of container images; 
 determine that the reference count for the data chunk is below a threshold value; and 
 in response to determining that the reference count for the data chunk is below the threshold value, prevent the client device from being queried about the data chunk prior to transmitting the data chunk to the client device. 
 
   
     
     
         2 . The system of  claim 1 , wherein the memory device further includes instructions that are executable by the processing device for causing the processing device to, in response to receiving the request from the client device:
 determine another reference count for another data chunk among the at least two data chunks;   determine that the other reference count for the other data chunk exceeds the threshold value;   in response to determining that the other reference count for the other data chunk exceeds the threshold value:
 transmit a query communication to the client device; 
 receive a response to the query communication from the client device; and 
 transmit the other data chunk to the client device based on the response indicating that the other data chunk does not already exist on the client device. 
   
     
     
         3 . The system of  claim 1 , wherein the memory device further includes instructions that are executable by the processing device for causing the processing device to, in response to receiving the request from the client device:
 determine another reference count for another data chunk among the at least two data chunks;   determine that the other reference count for the other data chunk exceeds the threshold value;   in response to determining that the other reference count for the other data chunk exceeds the threshold value:
 transmit a query communication to the client device; 
 receive a response to the query communication from the client device; and 
 prevent the other data chunk from being transmitted to the client device based on the response indicating that the other data chunk already exists on the client device. 
   
     
     
         4 . The system of  claim 1 , wherein the memory device further includes instructions that are executable by the processing device for causing the processing device to, prior to receiving the request:
 segment the plurality of container images into a plurality of data chunks of a predefined size, the plurality of data chunks including the at least two data chunks; and   for each respective data chunk among the at least two data chunks, count how many times the respective data chunk is present in the plurality of data chunks to determine a respective reference count for the respective data chunk.   
     
     
         5 . The system of  claim 1 , wherein the memory device further includes instructions that are executable by the processing device for causing the processing device to determine the threshold value based on a system constraint. 
     
     
         6 . The system of  claim 5 , wherein the system constraint includes a latency constraint, a memory constraint, or a processing constraint. 
     
     
         7 . The system of  claim 1 , wherein the memory device further includes instructions that are executable by the processing device for causing the processing device to determine the threshold value based a data-chunk size. 
     
     
         8 . A method comprising:
 receiving, by a processing device, a request for a container image from a client device; and   in response to receiving the request from the client device:
 determining, by the processing device, a reference count for a data chunk among at least two data chunks of the container image, the reference count indicating how many times the data chunk is present in a plurality of container images; 
 determining, by the processing device, that the reference count for the data chunk is below a threshold value; and 
 in response to determining that the reference count for the data chunk is below the threshold value, preventing, by the processing device, the client device from being queried about the data chunk prior to transmitting the data chunk to the client device. 
   
     
     
         9 . The method of  claim 8 , further comprising, in response to receiving the request from the client device:
 determining another reference count for another data chunk among the at least two data chunks;   determining that the other reference count for the other data chunk exceeds the threshold value; and   in response to determining that the other reference count for the other data chunk exceeds the threshold value:
 transmitting a query communication to the client device; 
 receiving a response to the query communication from the client device; and 
 transmitting the other data chunk to the client device based on the response indicating that the other data chunk does not already exist on the client device. 
   
     
     
         10 . The method of  claim 8 , further comprising, in response to receiving the request from the client device:
 determining another reference count for another data chunk among the at least two data chunks;   determining that the other reference count for the other data chunk exceeds the threshold value; and   in response to determining that the other reference count for the other data chunk exceeds the threshold value:
 transmitting a query communication to the client device; 
 receiving a response to the query communication from the client device; and 
 preventing the other data chunk from being transmitted to the client device based on the response indicating that the other data chunk already exists on the client device. 
   
     
     
         11 . The method of  claim 8 , further comprising, prior to receiving the request:
 segmenting the plurality of container images into a plurality of data chunks of a predefined size, the plurality of data chunks including the at least two data chunks; and   for each respective data chunk among the at least two data chunks, counting how many times the respective data chunk is present in the plurality of data chunks to determine a respective reference count for the respective data chunk.   
     
     
         12 . The method of  claim 8 , further comprising determining the threshold value based on a data-chunk size. 
     
     
         13 . The method of  claim 8 , further comprising determining the threshold value based on a system constraint. 
     
     
         14 . The method of  claim 13 , wherein the system constraint includes a latency constraint, a memory constraint, or a processing constraint. 
     
     
         15 . A non-transitory computer-readable medium comprising program code that is executable by a processing device for causing the processing device to:
 receive a request for a container image from a client device;   in response to receiving the request:
 determine a reference count for a data chunk among at least two data chunks of the container image, the reference count indicating how many times the data chunk is present in a plurality of container images; 
 determine that the reference count for the data chunk is below a threshold value; and 
 in response to determining that the reference count for the data chunk is below the threshold value, prevent the client device from being queried about the data chunk prior to transmitting the data chunk to the client device. 
   
     
     
         16 . The non-transitory computer-readable medium of  claim 15 , further comprising program code that is executable by the processing device for causing the processing device to, in response to receiving the request from the client device:
 determine another reference count for another data chunk among the at least two data chunks;   determine that the other reference count for the other data chunk exceeds the threshold value;   in response to determining that the other reference count for the other data chunk exceeds the threshold value:
 transmit a query communication to the client device; 
 receive a response to the query communication from the client device; and 
 transmit the other data chunk to the client device based on the response indicating that the other data chunk does not already exist on the client device. 
   
     
     
         17 . The non-transitory computer-readable medium of  claim 15 , further comprising program code that is executable by the processing device for causing the processing device to, in response to receiving the request from the client device:
 determine another reference count for another data chunk among the at least two data chunks;   determine that the other reference count for the other data chunk exceeds the threshold value;   in response to determining that the other reference count for the other data chunk exceeds the threshold value:
 transmit a query communication to the client device; 
 receive a response to the query communication from the client device; and 
 prevent the other data chunk from being transmitted to the client device based on the response indicating that the other data chunk already exists on the client device. 
   
     
     
         18 . The non-transitory computer-readable medium of  claim 15 , further comprising program code that is executable by the processing device for causing the processing device to, prior to receiving the request:
 segment the plurality of container images into a plurality of data chunks of a predefined size, the plurality of data chunks including the at least two data chunks; and   for each respective data chunk among the at least two data chunks, count how many times the respective data chunk is present in the plurality of data chunks to determine a respective reference count for the respective data chunk.   
     
     
         19 . The non-transitory computer-readable medium of  claim 15 , further comprising program code that is executable by the processing device for causing the processing device to, in response to receiving the request and prior to determining the reference count for the data chunk:
 identify the at least two data chunks in the container image.   
     
     
         20 . The non-transitory computer-readable medium of  claim 15 , further comprising program code that is executable by the processing device for causing the processing device to determine the threshold value based on a data-chunk size and a system constraint.