cron service not starting post docker run and container is getting exit - docker

Question

tried running cron through dockerfile but when running the container its getting exit. Below is my dockerfile and error. Any help would be really appreciated
Error:
docker: Error response from daemon: OCI runtime create failed: container_linux.go:380: starting container process caused: exec: "cron": executable file not found in $PATH: unknown.
Dockerfile:
# Pull base image.
FROM amazonlinux:2
ARG TERRAFORM_VERSION=1.2.6
RUN \
yum update -y && \
yum install unzip -y && \
yum install wget -y && \
yum install vim -y \
yum install bash -y
################################
# Install Terraform
################################
# Download terraform for linux
RUN wget https://releases.hashicorp.com/terraform/${TERRAFORM_VERSION}/terraform_${TERRAFORM_VERSION}_linux_amd64.zip
RUN unzip terraform_${TERRAFORM_VERSION}_linux_amd64.zip
RUN mv terraform /usr/local/bin/
################################
# Install python
################################
RUN yum install -y python3-pip
RUN pip3 install --upgrade pip
################################
# Install AWS CLI
################################
RUN pip install awscli --upgrade --user
# add aws cli location to path
ENV PATH=~/.local/bin:$PATH
RUN mkdir ~/.aws && touch ~/.aws/credentials
################################
# Install Cron
################################
RUN yum -y install ca-certificates shadow-utils cronie && yum -y clean all
# Creating crontab
COPY ./automation.sh /var/automation.sh
# Giving executable permission to script file.
RUN chmod +x /var/automation.sh \
&& echo "* * * * * /bin/bash /var/automation.sh" >> /var/crontab
# Ensure sudo group users are not asked for a password
RUN echo '%sudo ALL=(ALL) NOPASSWD:ALL' >> \
/etc/sudoers
#run cron process through cmd
CMD ["cron", "-f"]

Answer 1

Update the CMD to this:
CMD ["/usr/bin/crontab", "/var/crontab"]

Answer 2

Anyone looking for answer to this, I had to change the approach a bit of running cron and it worked finally. Here is the dockerfile with updated approach.
# Pull base image.
FROM amazonlinux:2
ARG TERRAFORM_VERSION=1.2.6
################################
# Install Dependencies
################################
RUN yum update -y && yum -y install unzip wget vim bash procps python3-pip jq git && pip3 install --upgrade pip
################################
# Install AWS CLI
################################
RUN pip install awscli --upgrade --user
# add aws cli location to path
ENV PATH=~/.local/bin:$PATH
RUN mkdir ~/.aws && touch ~/.aws/credentials
################################
# Install Terraform
################################
# Download terraform for linux
RUN wget https://releases.hashicorp.com/terraform/${TERRAFORM_VERSION}/terraform_${TERRAFORM_VERSION}_linux_amd64.zip
RUN unzip terraform_${TERRAFORM_VERSION}_linux_amd64.zip
RUN mv terraform /usr/local/bin/
################################
# Install Cron
################################
RUN yum -y install ca-certificates shadow-utils cronie && yum -y clean all
# Creating crontab
COPY ./automation.sh /var/automation.sh
# Giving executable permission to script file.
RUN chmod +x /var/automation.sh \
&& echo "* * * * * /bin/bash /var/automation.sh" >> /var/crontab
RUN crontab /var/crontab
# Ensure sudo group users are not asked for a password
RUN echo '%sudo ALL=(ALL) NOPASSWD:ALL' >> \
/etc/sudoers
#run cron process through cmd
CMD ["/usr/sbin/crond", "-n"]