The priority of kernel versions follows this order: Centos 3.18 > Ubuntu 14.04 > Centos 3.13. Therefore, Ubuntu 14.04 and Centos with upgraded kernel both meet the requirement. The default 3.10 kernel of Centos cannot provide proper support for the Docker overlay storage driver; only 3.18 and later versions can provide stable support. ECS does not allow kernel upgrade to prevent kernel incompatibility. The kernel used by Container Service has passed our compatibility testing. You can use ECS in the following methods:

1. Select automatic addition when adding a node. This can automatically replace the data disk with our system, freeing you from the concern for kernel upgrade.
2. Upgrade the kernel to elrepo 4.4 with a script. This kernel has passed our compatibility testing. The script is as follows: yum update -y rpm --import elrepo.org/RPM-GPG-KEY-elrepo.org rpm -Uvh elrepo.org/elrepo-release-7.0-2.el7.elrepo.noarch… yum install -y linux-firmware yum install -y perl wget acs-public-mirror.oss-cn-hangzhou.aliyuncs.com/el… wget acs-public-mirror.oss-cn-hangzhou.aliyuncs.com/el… wget acs-public-mirror.oss-cn-hangzhou.aliyuncs.com/el… rpm -i kernel-lt-4.4.6-1.el7.elrepo.x86_64.rpm yum remove kernel-{firmware,headers,devel} -y rpm -i kernel-lt-headers-4.4.6-1.el7.elrepo.x86_64.rpm rpm -i kernel-lt-devel-4.4.6-1.el7.elrepo.x86_64.rpm rm -f kernel-lt-headers-4.4.6-1.el7.elrepo.x86_64.rpm kernel-lt-devel-4.4.6-1.el7.elrepo.x86_64.rpm kernel-lt-4.4.6-1.el7.elrepo.x86_64.rpm echo "exclude=kernel*" >> /etc/yum.conf mkinitrd -f --allow-missing --with=xen-blkfront --preload=xen-blkfront --with=virtio_blk --preload=virtio_blk --with=virtio_pci --preload=virtio_pci --with=virtio_console --preload=virtio_console /boot/initramfs-4.4.6-1.el7.elrepo.x86_64.img 4.4.6-1.el7.elrepo.x86_64 grub2-set-default 'CentOS Linux (4.4.6-1.el7.elrepo.x86_64) 7 (Core)' You can also use the latest Centos 7.3 which is integrated with bugfix for overlay. Specify the parameter --override-kernel-check when adding a node.