A change to the kernel configuration on March 27, 2019, disabled the memory controller in cgroups. AWS Greengrass requires the memory controller to be enabled, and the memory controller is helpful for container managers like Docker. I'd like to request that the memory cgroup be re-enabled in the kernel config.
Edit: I see now that there is a kernel memory leak that is addressed by turning off the memory controller. It seems that we have to wait for an upstream fix.