diff --git a/appveyor.yml b/appveyor.yml
index 7fb45745a0..7fb22f1b0f 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -42,9 +42,9 @@ install:
   # Install maven and dependencies
   - ps: .\dev\appveyor-install-dependencies.ps1
   # Required package for R unit tests
-  - cmd: R -e "install.packages(c('knitr', 'rmarkdown', 'devtools', 'e1071', 'survival'), repos='http://cran.us.r-project.org')"
+  - cmd: R -e "install.packages(c('knitr', 'rmarkdown', 'devtools', 'e1071', 'survival'), repos='https://cloud.r-project.org/')"
   # Here, we use the fixed version of testthat. For more details, please see SPARK-22817.
-  - cmd: R -e "devtools::install_version('testthat', version = '1.0.2', repos='http://cran.us.r-project.org')"
+  - cmd: R -e "devtools::install_version('testthat', version = '1.0.2', repos='https://cloud.r-project.org/')"
   - cmd: R -e "packageVersion('knitr'); packageVersion('rmarkdown'); packageVersion('testthat'); packageVersion('e1071'); packageVersion('survival')"
 
 build_script:
diff --git a/dev/create-release/spark-rm/Dockerfile b/dev/create-release/spark-rm/Dockerfile
index 7ed9f7288f..45c662d0c0 100644
--- a/dev/create-release/spark-rm/Dockerfile
+++ b/dev/create-release/spark-rm/Dockerfile
@@ -42,8 +42,8 @@ ARG PIP_PKGS="pyopenssl pypandoc numpy pygments sphinx"
 #
 # This is all in a single "RUN" command so that if anything changes, "apt update" is run to fetch
 # the most current package versions (instead of potentially using old versions cached by docker).
-RUN apt-get clean && apt-get update && $APT_INSTALL gnupg && \
-  echo 'deb http://cran.cnr.Berkeley.edu/bin/linux/ubuntu bionic-cran35/' >> /etc/apt/sources.list && \
+RUN apt-get clean && apt-get update && $APT_INSTALL gnupg ca-certificates && \
+  echo 'deb https://cloud.r-project.org/bin/linux/ubuntu bionic-cran35/' >> /etc/apt/sources.list && \
   gpg --keyserver keyserver.ubuntu.com --recv-key E084DAB9 && \
   gpg -a --export E084DAB9 | apt-key add - && \
   apt-get clean && \
@@ -74,7 +74,7 @@ RUN apt-get clean && apt-get update && $APT_INSTALL gnupg && \
   # R depends on pandoc*, libssl (which are installed above).
   $APT_INSTALL r-base r-base-dev && \
   $APT_INSTALL texlive-latex-base texlive texlive-fonts-extra texinfo qpdf && \
-  Rscript -e "install.packages(c('curl', 'xml2', 'httr', 'devtools', 'testthat', 'knitr', 'rmarkdown', 'roxygen2', 'e1071', 'survival'), repos='http://cran.us.r-project.org/')" && \
+  Rscript -e "install.packages(c('curl', 'xml2', 'httr', 'devtools', 'testthat', 'knitr', 'rmarkdown', 'roxygen2', 'e1071', 'survival'), repos='https://cloud.r-project.org/')" && \
   Rscript -e "devtools::install_github('jimhester/lintr')" && \
   # Install tools needed to build the documentation.
   $APT_INSTALL ruby2.3 ruby2.3-dev mkdocs && \
diff --git a/docs/README.md b/docs/README.md
index 5b90f98cf8..670e9e0113 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -40,9 +40,9 @@ $ sudo gem install jekyll jekyll-redirect-from pygments.rb
 $ sudo pip install Pygments
 # Following is needed only for generating API docs
 $ sudo pip install sphinx pypandoc mkdocs
-$ sudo Rscript -e 'install.packages(c("knitr", "devtools", "rmarkdown"), repos="http://cran.stat.ucla.edu/")'
-$ sudo Rscript -e 'devtools::install_version("roxygen2", version = "5.0.1", repos="http://cran.stat.ucla.edu/")'
-$ sudo Rscript -e 'devtools::install_version("testthat", version = "1.0.2", repos="http://cran.stat.ucla.edu/")'
+$ sudo Rscript -e 'install.packages(c("knitr", "devtools", "rmarkdown"), repos="https://cloud.r-project.org/")'
+$ sudo Rscript -e 'devtools::install_version("roxygen2", version = "5.0.1", repos="https://cloud.r-project.org/")'
+$ sudo Rscript -e 'devtools::install_version("testthat", version = "1.0.2", repos="https://cloud.r-project.org/")'
 ```
 
 Note: If you are on a system with both Ruby 1.9 and Ruby 2.0 you may need to replace gem with gem2.0.
diff --git a/external/docker/spark-test/base/Dockerfile b/external/docker/spark-test/base/Dockerfile
index 224e7031fd..c1fd630d0b 100644
--- a/external/docker/spark-test/base/Dockerfile
+++ b/external/docker/spark-test/base/Dockerfile
@@ -32,6 +32,6 @@ ENV SPARK_HOME /opt/spark
 ENV PATH $SPARK_HOME:$SCALA_HOME/bin:$PATH
 
 # Install Scala
-ADD http://www.scala-lang.org/files/archive/scala-$SCALA_VERSION.tgz /
+ADD https://www.scala-lang.org/files/archive/scala-$SCALA_VERSION.tgz /
 RUN (cd / && gunzip < scala-$SCALA_VERSION.tgz)|(cd /opt && tar -xvf -)
 RUN rm /scala-$SCALA_VERSION.tgz