Not able to save crash dump using kdump

I have a VPS server on amazon's AWS Lightsail service. I've been testing kdump using the following two commands(to trigger an automatic kernel crash): # echo 1 > /proc/sys/kernel/sysrq # echo c > /proc/sysrq-trigger The problem is that the system crashed and rebooted, but there's no dump saved. Here is a list of checking I've done: [centos@server crash]$ systemctl status kdump ● kdump.service - Crash recovery kernel arming Loaded: loaded (/usr/lib/systemd/system/kdump.service; enabled; vendor preset: enabled) Active: active (exited) since Mon 2019-03-18 07:43:34 UTC; 5 days ago Process: 4119 ExecStart=/usr/bin/kdumpctl start (code=exited, status=0/SUCCESS) Main PID: 4119 (code=exited, status=0/SUCCESS) CGroup: /system.slice/kdump.service Mar 18 07:43:32 ip-.ap-northeast-1.compute.internal systemd: Starting Crash recovery kernel arming... Mar 18 07:43:34 ip-.ap-northeast-1.compute.internal kdumpctl: kexec: loaded kdump kernel Mar 18 07:43:34 ip-.ap-northeast-1.compute.internal kdumpctl: Starting kdump: [OK] Mar 18 07:43:34 ip-.ap-northeast-1.compute.internal systemd: Started Crash recovery kernel arming. [centos@server crash]$ dmesg | grep Reserving [ 0.000000] Reserving 256MB of memory at 368MB for crashkernel (System RAM: 2047MB) [centos@server crash]$ cat /proc/cmdline BOOT_IMAGE=/boot/vmlinuz-3.10.0-957.1.3.el7.x86_64 root=UUID=f41e390f-835b-4223-a9bb-9b45984ddf8d ro console=tty0 crashkernel=256M console=ttyS0,115200 [centos@server crash]$ grep -v ^# /etc/kdump.conf path /var/crash core_collector makedumpfile -l --message-level 1 -d 31 default reboot There's no log of the crash in the /var/log/messages indicating any error there might be. So I wonder what I might have missed. Or an AWS Lightsail VPS is not capable of saving a kdump at all...?